first i would say i'm glad that you opened the 7.0er EAP for VS 2010. Specially for VB there are many improvements which make my life more comfortable. Particularly the performance is much better than in 6.x.
But i also have problems with the build. I installed build 38 into VS 2010 and opened my 250.000 LOC solution. I got a bunch of OutOfMemoryExceptions while loading the solution and also as i start to edit the code. The startup problem i could solve by deleting all R# caches. But when i work some time on my solution the Exceptions occur again. In my case the exception was thrown by the Windows Forms desginer and not by R#. I had to restart VS to solve the problem.
[Edit] Additionally i just noticed that the Visual Studio instance where the exception occured was still alive after i've closed it (i could see it in the process list).