Well, I have an interesting case. A customer's site is in a particularly high competition niche. The basic details:
-His domain is an EMD (yeah, I know the "official story" on EMD's, but I find it still has value when all other SEO factors are in order, just not when the rest of the site sucks)
-Keyword is ~165,000 local search volume (exact match of course) for a high competition keyword.
Last year they were hit pretty hard by Penguin in April, and it took a lot of work to bring them back to decent first page rankings again. We've cleaned up their back link profile, which looks a whole lot better now and is much more natural.
With this latest Panda update, they've been bumped down 3 spots on the first page. Back in January they were #2 for a couple weeks, dropped to #3 where it's been consistently for a couple months, now dropped to #6.
The problem lies with a few competitors sites. They are micro sites which have been blackhat link builded to hell to the tune of roughly 1600 links per day for the top competitor. These few competitors have 15-31 TIMES more back links than my client's site. Their back link profiles all look horrible too, tons of links from irrelevant and completely unrelated websites, although many are high authority sites. One of the sites has something like 90% of it's anchor text to TWO keywords. Yeah, 90% of their backlink anchor text is with only TWO keywords (well, a percentage of it is long tail variations, but still the two keywords are present). No joke. I mean, I know how they did what they did. The problem is, this goes against everything Google says no longer works, or that their updates are targeting against, and yet these few sites have managed to succeed very well while my customer with a much more legitimate site has been bumped down in rankings.
I've also come to the conclusion that whitehat is dead UNLESS it's low competition, and unless you are the popular guy in the room everyone wants to talk about and talk to. Blackhat still works, it's just constantly changing. If you're not lucky enough to be in a low competition market, or that super cool popular guy, I think people are fooling themselves if they think bringing whitehat to a blackhat fight is going to win. I have always been all about whitehat, but I'm beginning to see that simply is not aggressive enough for many medium to high competition markets or niches. High quality blackhat with really high quality, readable and natural content seems to be the winning recipe for high competition stuff.