He does give some reasons, which might not apply to everyone is another thing: (from the article)
Because I love C#.
Because "MS is expensive" is a myth.
Because of Visual Studio
Of all the three I am very agreed with the third one. I wish it would be different but I haven't used a better alternative to VS so far (XCode, Eclipse, Netbeans, etc. just didn't work for me for several reasons ) The .Net Framework is extremely powerful and extensive.
The number of problems the framework has prevented me from needing to solve is staggering. We get work done here, fast.Eg. Recently I had to convert times from any random time zone into another random timezone accounting for daylight savings etc. I cannot imagine having to solve that problem in just about any other language suggested in this comment section.
In my experience you get more built-in with .net, but richer third-party ecosystems elsewhere.
I like C# a little more than Java, but I cant stand assemblies. Jars are much easier to handle.
edit:
Troll? Not.
Like a very simple thing: quick watch in debug blocks the edit window? Really WTF?! I have to move it the second screen to see the actual code. I can name a lot of these small annoyances.
You should try Kepler. Some amazing performance improvements out of the box.
I don't think this means much. It has (poor) support for just about every language under the sun and its free so of course its going to be widely used. It has many features for Java, but features for other languages quickly fall off a cliff. But its the slowness that is a showstopper for me unless I absolutely must go with eclipse. Yes, eventually computer technology will advance to the point where its bloated codebase is no longer a liability, and perhaps we're approaching that. I use the Juno release occasionally for python programming and everything I've mentioned still applies.
Personally I'm not a big fan of plugins in my IDEs: they always feel slow and clunky with a "bolted on" feel. This has been true of every IDE + plugin environment I've tried so far.
If you had said IntelliJ I might have believed it.
Also there's some clearly naivety when bragging about his "low cost" $200/month setup. His SQL Server licenses alone will probably triple or quadruple his costs when his Bizspark status runs out.
Maybe but believe it or not, there are people who HATE Java (that would includes me)
Regardless this post is not about .NET tooling, more about server efficiency and cost. Two areas where I think the JVM is a little further ahead.
Postgres, Oracle, MS SQL all support a (very large) common subset of features, so if you avoid stored procedures and db-specific features, you can port among them easily. This is not true for MySQL.
Added bonus: some versions will segfault if you pass an un-formattable date value.
Also while its great Microsoft is subsidising his starup via the Biz Stark program, we have seen many times what happens when you rely on "free" to run your buisness. Even tually he will need to start paying for those software licenses he is getting for free and by then he might not have a choice in what platform he is using.