Agility
Pretty agile. Stripes is another JSP based struts-like framework - but it seems to require a lot less artifacts than struts and also let's you throw up a JSP without having the backing classes in place so you can preview the page.
It makes pretty good use of annotations as well which can be more convenient than editing a bunch of XML files (although you can get a similar level of convenience with a Struts/XDoclet solution)
Plus the annoying problems of Struts indexed properties and nested properties seem to be solved here which is a major headache. But we probably won't be using forms like that anyway so it doesn't matter.
Support
The documentation seems pretty decent. There doesn't seem to be that much of a community around it though which could be a problem.
Skinability
Nothing special included, but I suppose you could integrate with Tiles...
Performance / Scalability
Not sure really, but I would imagine it would not be a problem - it's a not an unusual architecture or anything.
I8ln
Integrates with J2SE i8ln like everyone else, but does some stuff to make things simpler - like calling setLocale on every request so you don't have to.
Also has support in its validation framework for i8ln which is nice
Expression / Templating Language
JSP Tag lib w/ JSP Expression Lanaguage
Componentization
None.
Summary
Like
WebWork?, a viable contender for best re-working of struts.
WebWork? seems to have a larger community of developers, but stripes has better docs and what seems to me a larger (or at least more compelling) feature set.