I've been pretty pleased with Tapestry. It is a different approach than what most people are use to. It uses a lot of the same paradigm as WebObjects (what the iTunes store is built on).
Tapestry does a very good job of minimizing the amount of code you have to write to accomplish a task. This is great once you know what you are doing, but it can be frustrating at first while you are learning the naming conventions because some stuff seems to magically work and other things won't because you named wrong.
One of my favorite things about Tapestry is how little XML is required. For example, if you create a Hibernate entity, you place it in the com.example.entities package and give it the @Entity annotation. There is no other configuration necessary--no XML, no adding the the class name to a file somewhere, etc.
I'd highly recommend taking a look at actual code to see what you think. Here are a couple suggestions:
wookicentral.com/
github.com/spreadthesource/wooki
tapestry.zones.apache.org:8180/tapestry5-hotel-booking/
github.com/ccordenier/tapestry5-hotel-booking
Also take a look at the jumpstart site. It contains a number of examples along with the code showing you exactly how to use most of the various components. It also contains a starting point app that gives you some user management features if you want to base an application on it.
jumpstart.doublenegative.com.au/jumpstart/
Also check out the revamped Tapestry documentation. It isn't posted on the main site yet, but it is already a very big step forward:
people.apache.org/~uli/tapestry-site/