Resharper is indispensable for me. Code is better by a factor of 2 while it's there to remind everyone of a common style and template. I have used it on a project that had ~1 million loc and 250 projects and didn't find an issue with it slowing the ide. You need to be careful with having other extensions that monitor code in real time as that is the big cause of slowdowns and deadlocks. I'm looking forward to trying this one out.