anyone have any experience of using them together? How well does it work? or is it just too much grief?
I've used Resharper for awhile and recently installed the free Coderush Express too. After a week or so, I can say that Coderush has not gotten in my way in the slightest, nor has there been contention between the two tools. Admittedly, I'm way more familiar with Resharper and wouldn't know if half of Coderush was not functioning, but I'm pleased with this set-up currently.
Update: the tab key to go to other usages in CodeRush sometimes interferes when trying to complete a type in a template. For instance, typing foreach creates a foreach template. If while editing the template fields, tab is hit, say, to complete the entry, CodeRush zips you to some other place. Thankfully Esc recovers from this.
See the comments for advice on remapping keys.