In my opinion, the power of
JSF is in its ease of use, and I think this is where it competed directly with .NET
Visual editors for JSF (JDeveloper and
Java Studio Creator) are both very powerful and make developing web based applications as easy in Java as they are in .NET
If you can develop JSF apps as quickly as you can develop .NET apps, then the whole argument of which to use becomes somewhat diminished (at least from a technical point of view ;) )