We've built our app (http://keypay.com.au) on .net and have zero complaints so far. The best thing is that with AppHarbor, it makes it easy to spend less time focusing on "the stack" and more time focusing on just getting stuff done.
We build fast, release often and the .net stack is so mature that we spend very little time thinking about it and the majority of the time solving business problems.
We build fast, release often and the .net stack is so mature that we spend very little time thinking about it and the majority of the time solving business problems.