I was one of the chosen testers for the final product. I didn't notice much difference at all.
There are some changes (I'm told) to the Amazon App, but there is no Amazon Widget. Several comments were made about calling it a widget, but I guess they decided to go with that terminology anyway. I don't use it so I really couldn't do much evaluation.
The News and Weather Widget now has better connectivity and the previews in the news contain thumbnails. I have played with this in the past, but do not use it so it really didn't matter to me.
As for the Twitter App, I don't tweet, so I didn't even open it.
I have had my Droid since mid-January and have never had any screen lag with the built-in launcher, but I can say I also saw no lag with the update.
There are supposed to be some tweaks to help battery life and some testers claimed they were seeing better battery life, but we only tested for about three days, so who knows how good that info is.
One thing that was almost unanimous, the phone seemed a bit snappier. Nothing to alert the media over, but a little.
I don't use exchange, but those testers that did seemed to be impressed.
We were told that there were other tweaks under the hood, but that wasn't elaborated upon.
Overall, a good update for stock folks and a move in the right direction. After spending the time to unroot, reinstall everything and test for three days, I immediately reloaded LFY 1.95 and the Tangerine theme and went back to my rooted and overclocked phone that works great.
If asked to test again, I'll do it again. It was an interesting experience and, who knows, maybe one day I'll get to test something revolutionary.
BigRedGonzo