The big thing I tried for this which I've tried for the earlier versions of 2.1 that were leaked, 3d acceleration has improved GREATLY.
For example, I've tried the Speed Forge 3d demo on dd03 and dc23(Or whatever the other leaked build was) both were not playable, there were textures that were completely whited out, unresponsive, and very very low fps. Where as now, all the textures show up, the game loaded within 3 minutes this time lol. It's still a tad slow, but considering that all the textures are showing up it's an improvement.
Live wallpaper hack still works for me no problem, but when Live wallpaper is enabled the phone just drags. I'm thinking I just need to reinstall live wallpaper fresh on this new build.
I haven't tried JIT, as everytime I did on dd03, I always had random resets no matter what.
Feels snappier, Gallery was reverted back to the original gallery app, and the phone is much more sensitive now to putting it on it's side and rotating. I like that a lot actually. The big thing was for me, I didn't have to completely reset my phone. Contacts are no issue as they are linked to my google account, but it's annoying to have to download my apps over and over lol. I should probably back them up. It did however revert back to the stock theme. Which is no issue, I expected that.
Did find something else, after I installed the 2.1 gallery app, it didn't replace the original gallery app. So now I have 2 gallery apps, the stock app, and the 2.1 ported app. Not a big deal though.