I wrote an extensive review of IE9 on my blog that took hours to write as I wanted to cover everything to be fair. Microsoft did put a lot in to building IE9 and it has come a very long way...but then again they had to. Here's a brief objective summary...

Standards Compliance
Microsoft apparently stuck to the more mature specs with the intention of having IE9's rendering to not be different IE10 between what standards compliance they share. The upside? Well for the features that did make it to IE9 there will likely be fewer bugs compared to later versions of IE. The downside? IE9 is a bit boring...sure there's border-radius, multi-background image support and 2D transforms though how long have other browsers had multi-column layout and transitions? There will still be a lot of JavaScript needed to add DHTML animations over the next decade or so in example.

Performance
IE9 is fast though not because of hardware acceleration. They really did do a good job with the software as my site's DHTML animation for hiding and showing the sidebar is smoother than Chrome, Firefox and Opera 11.1 and earlier though it's about even with Opera 11.5 when it's hardware acceleration is taken in to account...and it works with the hardware acceleration on XP without any problems, can't say any of that about IE9. Still the performance is really good.

Graphic User Interface
Total devastation, it's absolutely unusable. The buttons are way too small to click on without making unnecessary amounts of dexterous effort, not good for browsing be it casual or production related. None of the controls can be customized or given text labels so non-technical users won't know what all of them do. Blocked ActiveX content? Yeah a small little blue circle with a cross isn't going to help non-technical users. The download "manager" is difficult to find and the window only seems to appear when a download has completed and you have to click at least twice to get to it. Technical people will say key-strokes, non-technical users don't use keystrokes and that is the intended audience for IE9.

Recommendations
Would I use IE9? No, it's not available for XP and because Microsoft has been busy intentionally destroying the GUI of it's products like Vista, 7, Office, Fiddler, etc I will leaving Windows XP for Linux eventually. I'll still use it to test my work of course though that's about it.

Would I recommend this to technical users? Unless you build websites no though since IE is deeply embedded as part of the operating system you should have it installed though I wouldn't recommend using it.

Would I recommend this to non-technical users? No, the GUI has been butchered and it's simply not usable. If a user is unlucky enough to already be running Vista or Windows 7 I would make sure it's installed though have them using a different browser, Firefox or once Opera reaches 11.1 stable.

Looking Forward
IE9 is on par with Firefox 3.5 on SVG, roughly on par with Firefox 1.0 in regards to CSS3 and subjectively on par with Chrome 10 on performance. Since it's not available for Windows XP IE9's market share will not surpass that of XP's market share at any point as IE10 will be out before XP comes close to being surpassed in combination of Vista and 7. IE9 does however put Microsoft in a position to pull ahead of all the other browsers if they manage to put the same amount of effort in to IE10 as they did with IE9 however they'll have to wade in the waters of specifications that are less mature so we'll certainly see a lot of CSS properties with -ms- prefixes in IE10 if Microsoft remains serious about standards compliance. IE9 is a nice browser though it's still a couple years behind in some ways...the performance is pretty good though. Not supporting XP is the Achilles' heel for this release however and Opera doesn't have comparable resources to Microsoft and they still managed to get as far as they have so Microsoft is more than capable of getting IE9 to work on XP however they're now more interested in reducing productivity. This is an opportunity for the Linux community.

- John

Total devastation, it's absolutely unusable. The buttons are way too small to click on

They are small, and I thank Microsoft for that, cleans up the whole interface. Why make buttons that most people use only now and again any larger.

My only suggestion for furture updates is I would like to be able to make the text in my favourites smaller as they seem to be more spaced out now and consequently take up more space.

Or I would like a favourites folder which takes all the favourites links I use every single day and places them in one folder, and updates each week. I could do it myself but......

At SXSW, MS had a pretty cool display with two monitors, one running Chrome and the other running IE9. They had graphics of a school of fish swimming around, and the IE9 display was smooth and fast while Chrome was slow & jerky.

I'm sure the test was carefully staged to highlight a Chrome weakness, but it was still interesting to see that MS has finally realized people value speed.

Was hoping this was going to be a FF/Chrome killer but sadly MS has under delivered. It's not faster than Chrome/Opera. Oh well at least MS got Windows 7 right.

No, it's not available for XP

Not supporting XP is the Achilles' heel for this release

XP is like the IE6 of OS's, go away already! its 10 years old!, people weren't crying about windows 95 in 2005

I have been using this version for a day now and find old sites displaying poorly. Seems to not recognize quirks doctype. To me this is a huge problem, as one reason I use IE is because it displays more old quirk sites well compared to other browswers.

Also, most text here at the forum displays centered and not left...

@Jon_King, I don't see that centering issue that you describe.

I know it has been said before, but really? Beautyoftheweb?

Isn't it time someone wakes up MS?

My experience:

IE9's standards compliance is definitely much better than before. Rounded corners and standard opacity, hurray! The downside is that you have to add an "if lte IE 8" conditional to use the old IE filters on IE8 and earlier.

(There's also a serious rendering bug introduced in IE8 that wasn't fixed in IE9RC, but I haven't tested with IE9RTM yet. I'll test again and report back as to specifics.)

If you're over 40, you likely won't like the miniaturized address bar buttons. One special issue is that "Compatibility View" highlights on hover with the same color as that for "Refresh", which encourages misclicks. Sure, I could click F5 for refresh, but on my laptop (like many others), clicking F5 means clicking a function key in tandem to get access. Clicking a browser button with my mouse is easier. And I want that button to be bigger and easier to distinguish from other buttons.

As far as performance, IE9 seems to load slower than IE8, but once it's loaded, it's faster than before.

I meant 'pressing' instead of 'clicking' with reference to the F5 key.

As far as performance, IE9 seems to load slower than IE8, but once it's loaded, it's faster than before.

are you sure its not cache built up in IE8 vs IE9 being fresh with no cached content?

are you sure its not cache built up in IE8 vs IE9 being fresh with no cached content?

I don't follow. If IE9 takes much longer to load based on a similar-sized cache that IE8 had, it would seem to be IE9 that has the performance issue there. What am I missing?

How does IE9 compare to Firefox loading? I find FF to be brutally slow.

The "fish tank demo" [ie.microsoft.com] that rogerd mentioned is available online, if anyone wants to compare browsers with it.

It uses the HTML5 canvas element to draw the swimming fish swimming. The FPS count tells you how many frames per second the browser is able to draw, and it uses a png sprite approach to create the needed images.

@Fontiman
Heck, I wait a day and all the visual problems with the new install went away. I do see some files automatically updated by MS... must have solved my problems behind the scenes.

Now as I surf the doc mode changes as required, when I know for a fact it did not in the first 12 hours of use. All I know is it works fine now.

Ditto what has been said, in Vista and 7, faster, smoother and better layout.

Based on my testing, the rendering bug in IE8 that I alluded to has indeed been fixed between RC and RTM. Here's a link to the bug on the MS site: [connect.microsoft.com...]

Bug Description: "Overflow: scroll causes element to always have its max-height." I assume this also applies to overflow: auto, which was my case.

Separately, a bug that has been seemingly introduced in IE9 is that in a particular case, jumping to an anchor fails. After closing a JavaScript-called window and reloading the calling page with a #jump to an anchor, it doesn't jump. YMMV, but that's what I'm seeing. This works as expected in previous versions of IE and all other contemporary browsers.

Is there any chance we can install this side by side with 8? Or at least keep 8 available somewhere for testing?

And as for Chrome being spyware: you can always install Ghostery to block any data mining.

I've found IETester to be buggy with regards to JavaScript, but it has been a reasonably good tool for comparing IE8 rendering to the IE9 I have installed. Link: [my-debugbar.com...]

...about 47,37 % of my Windows users have XP installed (numbers are for 2011 which are around one million visitors and Windows acccounts for about 70% of all visitors). I don`t get it, this must be unreal how MS is giving away market share for free, FF (with version 4) has no problems with XP, but MS with his own product?

viggen I aggree. The web imo is for surfers not software. It sould work for as many surfers as is reasonably possible/feasible? Seems like a poor move on MS's part.

I also get miffed when functionality is removed. Man, I miss my search bar and its dropdown with different SEs to use for the the same queries.

How does IE9 compare to Firefox loading? I find FF to be brutally slow.

Depends a lot on the configuration. For regular browsing of html sites (blocking active scripting in general) all browsers are fast. I don't see any noticeable differences.

But if you see slow response from a browser check the settings. FF can be very slow if you have buggy plugins which don't release resources. Same goes with chrome and various IE versions when they just lock up on pages because of complex scripts (especially when timers are involved).

Now the other day when I was using IE9 trying to purchase something online I could see intermittent problems with buy now and checkout buttons. I ended up clicking the wrong dispatch address on my account. These compatibility issues are not very nice for sure.

And is too early for me at least to say if it's good or not the way IE9 is marketed. In few years time webgl will be on the rise. So for a product to be successful I guess graphics and platform requirements should be at the top of the list.

Pushing for a specific browser on a specific platform with a specific graphics technology is just not too user attractive these days.