Let me start out by saying I'm a huge fan of JetBrains ReSharper. When DevExpress CodeRush started gaining traction, I gave it a try and instantly new all its bells and whistles didn't stand up to the code analysis intelligence ReSharper provides - it is simply un-matched. Until now...
The upgrade to 4.5 was excellent for the most part, however, the performance problems in v5.0 BETA are disastrous within an ASP.NET / VS2008 environment. This experience has been horrible. R# has literally crippled visual studio past the point of frustration. The code-behind .cs is sluggish and .aspx analysis is insanely poor.
This has nothing to do with hardware as we're on brand new Dell workstations (dual/quad-core, 4GB RAM).
Solution-wide analysis was never turned on either.
My BETA analysis:
JetBrains, stop adding features (patterns, internationalization, etc) and revamp your engine. Now, please!
A couple months ago I gave CodeRush another try, and while it still isn't as bright and insightful as R#, it's an absolute pleasure to work with and zero performance hits. It's template engine is incredible to say the least.
If there's more information I can provide, please let me know. I'm still a fan of your product, but will not be able to recommend v5.0 as of yet.