The first two books on your list are both decent resources, although I haven't found either one to be considerably more detailed than the other, and I haven't read the Wrox book on Struts.
I found Sue Spielman's book
The Struts Framework-A practical Guideto be a great overview, and it also provided practical advice such as best practices for transfering data from the model to the view.
Programming Jakarta Struts is a good intro to the newer features in 1.1, and I use it often as a reference, but it's not what I would call a beginners guide. The only one of the group I have read cover to cover was
Struts in Action, which I felt was the best place to start for a reasonably experienced developer who wants to learn Struts.
I still think I've learned more practical stuff about Struts on the web. I will generally check here at the 'Ranch or do a google search on what I want to do, and chances are there will be an article somewhere or a
thread on a mailing list that will answer my questions.
HTH,
E
[ December 04, 2003: Message edited by: Eric Fletcher ]