I've been using ReSharper now for about one and a half weeks.  Now that I am writing some new code, I have more to share.

The most helpful and time saving feature that I have encountered so far is code generation.  In one case, I had added a couple of new properties to one of my entity objects.  In actuality, I add the code in my test first.  R# quickly recognized that the property didn't exist and gave me the option to create a field or property.  I chose the property option and presto, R# found my class and added the property.  It can do this with interfaces to.  This makes TDD that much easier.

I also started using the refactoring tools more as well, and they are very impressive.  I have used Refactor!Pro in the past.  One of the things I like about R!Pro was that it would let you chose where you want to place a newly extracted method.  I haven't seen that yet in R#.  Perhaps it's an option somewhere.

I still occasionally see some ASP.Net issues with resolving control references, but I basically ignore the red text and I modified the R# options to use VS intellisense instead of R#.  Then at least, I can get Intellisense even when R# thinks (incorrectly) that there is an error.