We've previously developed a system using Tomcat 4/JBoss for a J2EE style development.
I won't bore you with the details here, as I hoped to post up a more formal comparision at some point.. but what I can tell you is..
I'll definately be pushing customers even harder toward OACS. I think the big problem that Java based solutions have in the web world is, and I apologies for paraphrasing Mr. Greenspun in this, is:
Websites are pretty easy.
Java is pretty hard work compared to TCL.
The web is strings based, Java is not (TCL is).
It takes *at least* twice as long to do a service in a Java stylee as it does to use the OACS.
Although Tomcat 4 is pretty quick... JBOSS runs like a dog... therefore benefits lost...
I still haven't found a better more all-round web server than AOLServer.
I can't stand compilers! (Thats a purely personal preference)
But most importantly, the Java community is almost TOO big. Its full of good ideas, good startpoints and lots of clever people doing their 'thing'. Unfortunately I did find that it lacks coordination and too much software is re-inventing wheels, or just never really gets finished.
I still think OACS wins over VS a Java approach, if for no better reason than, its matured better.
I do hope to write up a better comparison of the the two projects I'm referring to, but not quite had time yet
