Derek Sivers spent two years trying to make Rails do something it wasn't meant to do, then realized his old abandoned language (PHP) would do just fine if approached with my new Rails-gained wisdom.
Small-scale benchmark test run on 9 languages or variants: Java 1.3.1 and 1.4.2, C via gcc 3.3.1, Python 2.3.2 and via Psyco 1.1.1, 4 from Microsoft Visual Studio .NET 2003: Visual Basic/C#/C++/J#.
Thorough article by Dare Obasanjo, treats most similarities and differences between the two languages: features in Java and not in C#, and features in C# and not in Java. Text, tables, code, resources.