There is always a debate regarding quality vs quantity...my blog is closely associated to my work....I would like to build it up quickly but I restrict myself and concentrate on quality as opposed to quantity.

I believe that a single good quality post every day will be far more beneficial for me rather than many posts everyday with content that does not add any value to my blog...

however, I am talking about a niche blog that I am managing independently....look forward to other inputs...

To me the main question seems to be whether they are doing this full time or just as a small part of their workday. If they're full time, there had better be some real link bait in their posts--controversy, unusual information, intelligent and informed passion, etc.--otherwise, your ROI numbers aren't going to look real hot.

I know that for the company I work for, we hired a copywriter to produce link bait full time (inlcluding blog posts), and even writing a ridiculous number of articles and posts all day every day, it wasn't a great investment because what traffic there was wasn't converting. (I think the non-converting traffic had as much to do with the nature of our industry than the quality of her posts, BTW.)

On the other hand, if you have a couple of non-professional writers who are passionate about your industry, their passion and knowledge should allow them to write a really solid post every now and again that attracts real enthusiasts for your industry. And having them double as writers (even if they're not "pros") in addition to their other duties would seem to make business sense--they're doing something they enjoy/are passionate about, and you're getting link bait without paying for a full time copywriter.