subitting spam report is the worst thing you can do - it is just not fair. probably all their sites are good enough to rank where they rank.

your best strategy is to fight your way up on fair play basis and not being an a$$hole.

Entering a saturated niche is difficult, not impossible. Ultimately a good back link profile will do wonders... it is obtaining them that is the difficult part. Offer a clean, good content site, get a few back links, and go from there.

Eventually one reaches a point of diminishing returns (ie. work expended for traffic/rank received). Most of the time that point becomes obvious and at that time one should move on to other things.

submitting spam report is the worst thing you can do - it is just not fair. probably all their sites are good enough to rank where they rank.

Multiple sites with largely identical content all deserve to rank?

This is a comparison shopping type search. Multiple sites from the same intermediary reduces the choices people see.

It is deceptive, as most visitors will not realise all the sites belong to the same business.

What about their use of paid links, splogs, irrelevant link exchanges, etc?

The second biggest competitor in the niche has multiple sites, each targeting a different niche, each with different information on it, and the same design and logo so its completely clear you are dealing with the same business. That is fair enough.

@tangor, thanks for the encouragement. I was thinking on similar lines. The site will hopefully get a bit of a boost as I am reimplementing it and will improve on page SEO as part of that. From there, do a bit at a time and see how it goes.

Are you 100% sure the content is identical? We often look at others' sites and think they're same same, while they're not. Maybe Google found each site is actually different and that's why it displays them.
I, too, have a competitor who have spammed all our local playground with his main website's clones, but I have never thought of reporting him. That's how losers act. And it won't work, either without getting some decent backlinks.

I noticed network guys work on similar backlink profile or cross-link their sites. Quite often, a couple very good links can help. Perhaps you can try a press release to make it to the news sites and maybe a blogger or two write about you.

Are you 100% sure the content is identical? We often look at others' sites and think they're same same, while they're not.

Yes, word for word identical text, in some cases with the same pictures. Essentially each of the smaller sites contains a subset of the main site.

I, too, have a competitor who have spammed all our local playground with his main website's clones, but I have never thought of reporting him. That's how losers act.

I disagree - they deserve it. Even if it does not help the site I am working on, it will still improve the SERPS for users.