We've got allot of different Uk websites in different niches, thought it might be interesting to share our experiences of the big changes so far. All sites have seen some change, more than we'd expect in a normal couple of months. All in all the serps have evened out. To be fair to Google the phrases where we were punching above our weight have dropped and those where we have been undervalued have risen. Two of our sites have fallen, the first had poor quality content (lazy client) and the second was an ecommerce store again with lazy content (client underinvesting). All in all I'd say that whilst the changes haven't completely favoured us I'd say that they are fair. What we are noticing is that having links is no longer enough. Having links gives you the chance to rank but unless you've got great content it doesn't count for much. On the flip side, if you've got a poor quality backlink profile, it will put you in Google's cross hairs, but currently, if you have good content and more importantly strong brand signals it's not pulling the trigger.
In my opinion Google is as culpable for the mess that's out there as much as anyone. They made the rules and turned a blind eye for so long that they forced people to do what they dont always want to do to make ends meet. It seems to me at the moment that they've taken a mature step to fixing it. Dont penalise the rubbish, reward the good because at the end of the day Google is the single most cupable party in encrouaging the rubish in the first place.
I pick-up that most people on here have ecommerce shops. What I've just said doesnt completely apply to you guys. Googles clearly screwed up with the over optimisation filter and is grabbing all similiar products as duplicate content. that cant go on for ever, I'm sure Google will fix it for you, otherwise they're going to look a little silly :)