I use .Net and Java stack, I don't want to start a war here but I never felt held back due to any reason for developing web apps in either of the two. For mobile apps, its a different story, I stick to phonegap.
I found a lot more support online for other stacks.
For example, I wanted to do a tiny webpage, and host it online cheap or for free. The cheapest options were Google App Engine and AWS.
I looked into Azure pricing and ran away. I'm probably ignorant of the best solutions (Rackspace seems to have a startup program, there was a .NET hosting I liked, there's also BizSpark), but most .NET hosting was a lot more expensive than I wanted, and not supportive of "weekend project" types.