[ayers]

The startup that I work for is built on .NET using C# and ASP MVC. Licensing costs were not a barrier/concern as we were part of the BizSpark[1] program. This gave us free access to all the Microsoft software we needed. We only recently graduated out of that so it will be interesting to see what affect that has on some of our future tech decisions/directions.

Visual Studio is an amazing IDE and C# is a top notch language. The price you pay for that is worth it and shouldn't be an issue for a profitable startup (which you should be by the time you graduate the BizSpark program). Like others have said, the bigger issue is that it ties you down to all the other Microsoft licenses such as Windows server.

I know of other startups that are using C# and .NET and run a mix of Windows and Linux(Mono) servers. This has forced some decisions for them though, such as rolling some of their own frameworks/tools that work nicely with Mono.

[1]: http://www.microsoft.com/bizspark/