Good writeup, and I agree with much of his post. Going back to Java from C# at the language level is just painful.

The Java library/framework is more complete and diverse than the .NET one, but it's actually improved alot for .NET in recent years with Microsoft becoming much more open source friendly, the ALT.DEV community, Mono, etc... The .NET community is much more comfortable with alternative not from Microsoft these days than in the past.

IMHO though, the JVM has a better alternative language ecosystem than the .NET one. Yeah, .NET has F# builtin to VS these days, but doesn't have things like Scala/Clojure (not first class citizens), Kotlin, Ceylon, etc...