I still can't use ReSharper when I'm working on SharePoint proejects because it doesn't recognize the Microsoft.SharePoint.WebPartPages.WebPart object. Since every WebPart inherits from this object it makes things too confusing (everything compiles fine but there are red squigglies everywhere in the code).
It is also hard to use with projects that do a lot of XML serialization because things like XmlAttribute are still confused with XmlAttributeAttribute and such.
I've not heard any reports on the status of these types of (for me at least) show-stopping issues. Sure I like the refactoring, the enhanced intellisense (when it works), and the code coloring, but I need it to be usable.
For now I just turn ReSharper off (which works great as long as I don't open Tools->Options since ReSharper options crash VS when ReSharper is unloaded) when I working on projects that have these issues.
ReSharper has a lot of promise so keep up the good work (and fix these issues ]]>)!