Regarding Wicket itself: I really like this framework (we use it in my current team and it produces nice UIs that are pretty easy to maintain and change). Why do I like Wicket? Well for the following reasons:
- Its Java based, and since I'm strongest in Java it suites me.
- There is a nice separation between the UI in HTML/CSS/JS and the java code that backs it. This clear separation between the presentation/design aspect and the coding is useful because it separates along the common skill groups. JavaFX (can you say "designer/developer workflow") may change my opinion on this but right now I see advantages over say the JSP approach.
- Testing is well covered (with WicketTester) over and above just using something like Selenium (also mentioned in the book).
BTW...I love manning books. The fact that you can get a free ebook when you purchase the print copy is excellent and in general everything I read from the publisher is superb.