It's really nice being able to trace into the guts of hibernate, spring, etc to see what the heck is actually going on and fix it if it's broken. When I used to do Microsoft stuff, I'd run into bugs in the stack that I couldn't fix. This was enormously frustrating and time wasting. The typical advice given out by support was re-install or buy the latest upgrade. There were also a lot of deliberately imposed architectural limitations to prevent you from working around lack of "enterprise" features in the basic versions which were incredibly frustrating and the enterprise version pricing was astronomical.
The open-source situation at Microsoft has really improved. Source is available for a lot of their web stack, contributions are accepted, and there are some nice open-source frameworks (like Nancy, MIT-licensed, inspired by Sinatra) that run on IIS or another Owin-compatible server these days.
I generally prefer Ruby-based things myself - this post isn't trying to sway anybody to the MS side; just wanted to give a bit of credit where it's due and perhaps a bit of news to those who haven't looked over onto that side of the fence in a long time.
