Since I installed the v2 update, Visual Studio has been hanging on occasion. The CPU for the process jumps to 25% and stays there and Visual Studio stops responding. I found a Microsoft Connect feedback which describes the same problem. It seems to be connected to intellisense for Knockout. There is a registry hack to turn it off, and this has worked for me. On March 13th, they report that the fix will be in VS Update 2, which is currently in CTP4 state (on March 19, 2013) with a “go-live” license.
Update (April 4th, 2013): Officially released today: http://blogs.msdn.com/b/bharry/archive/2013/04/04/vs-tfs-2012-2-update-2-released-today.aspx. This has been fixed: according to Xinyang Qiu.