I liked it it seems more stable and less memory-hungry than 2010 (Which is good seeing as how 2010 was far less stable than 2008). The XAML editor is particuarly improved.
I also prefer the new colour scheme and syntax highlighter. Intellisense much improved.
The downside is they are dropping "out of the box" XP support as a target!) for C apps, by using the new runtime. The other downside is that its going to very pricey to do yearly upgrades for me, seeing as im not going to be a student anymore. For me, im unsure if its worth upgrading.
Yes jbennet STUDENTS get the professional edition free from Dreamspark. However I don't think it is going to come out until the final release. After the beta that is. I got the professional edition, and Expression Studio ultimate all for free! :D
On top of that, I am so lucky that I can actually sell 100 aps for free in the Windows Phone Market (free registration as well), but that's only if I put my head down and make something!