This Beta 2 should be more stable. The VS team also put a lot of effort (so I hear) on performance improvements.

http://msdn.microsoft.com/en-us/vstudio/default.aspx

As always, Scott Guthrie knows how to give us the headlines, best way possible:

http://weblogs.asp.net/scottgu/archive/2009/10/19/vs-2010-and-net-4-0-beta-2.aspx