There is nothing more important than not being stuck with using a tool everyday for 8 hours a day that you hate.

After using R# everyday with Visusl Studio for years, I got a job that wouldn't provide Resharper for developers. I bought it myself without a second thought. I want the tools I use to be seamless as possible.

As far as the other reason I chose to base my career on .Net rather than Java once I decided to move away from C++ bit twiddling - that I trusted Microsoft to evolve the platform more than Sun, in hindsight it seemed prescient.