Hey Ropekid, not to bring up a dumb systems argument but did you enjoy 4e?
I'm still playing it, and yes. I've played more 2nd Ed. than anything else, but at this point I've played a fair amount of 4E (still less than 3E/3.5 and 1st Ed. but more than Basic/Expert). I think the way that WotC split the core races/classes between PHB1/2 was a practical and transparently cynical way to promote more sales of both handbooks, but I like the rule system overall.
My current campaign is in Paragon tier and the combats are getting slow. I timed out how long each player takes to act in real time, and it averages over 2 minutes, which is not good. The biggest chunks of time seem to be a) picking what to do (often paying attention can help alleviate this, but the long turns per player make it difficult to stay focused) b) calculating attack rolls and c) calculating damage. Those may seem like "no duh" things, but I was kind of floored when I actually paid attention to how much time people spent doing them.
Skill challenges are terrible. I don't think I need to really argue the position as I think almost the entire universe agrees with me on this point.
I disagree with George's statements about role-playing potential in 4E vs. other editions. I also don't think the classes feel that similar -- outside of each class possessing the same number of abilities/powers/etc. Even at low levels, my warden and my bard felt very different from each other and very different from the other PCs.
Our current campaign is Scales of War, and I have been disappointed by the role-playing potential in the modules themselves. There really isn't a lot of room for adjusting the course of the story or making moral/ethical choices, so I have been bummed out about that. Our DM has still found ways to insert role-playing opportunities into the campaign based on our backstories and choices we make with his (added) content.