I want to write a visual studio addon to do some code modifications for me (like some specific refactoring). I was wondering which one of these tools should I use and why?
we have licenses for resharper, the other two are free and this is an internally used software, so we don't need to worry about licensing.
If you've figured out the ReSharper API sufficiently to do useful work with it, then you should sell your knowledge to the highest bidder. They've been promising documentation for the past three major releases.