MVC frameworks

I've been using Struts MVC framework for a while. It's a solid and very popular framework. So popular that sometimes we forget to check what else is there... In my little research I came across with two very different frameworks: WebWork and the Spring Framework.
WebWork seems to have an aproach very similar to Struts. However, it feels like an improved Struts (no more ActionForm's :) ). However, I didn't analyse it too deeply, so I can't tell all the advantages/disadvantages.
To be true I gave much more attention to our second contestant: the Spring Framework. This one is quite different. It's much more than MVC (MVC is just one of the modules). In fact, you can use WebWork or Struts along with Spring...flexibility is the key :)
I'm doing some experiments with it....I'll post some of the things that I find in here.