Why is JBuilder evil?

Among all the other things I do that suck up my time, I read the two main Struts mailing lists. On struts-user, there is periodically a message or two observing that JBuilder is the Worst.Tool.Ever!!!1! or similar unsupported statement.

Do either of you readers know what they're talking about? I use JBuilder all the time, and find it an excellent tool worthy of my attention (not least because I can get "vi" key bindings in it, and we all know that CUA and EMACS are the sperm of the devil).

What gives? What's so evil about JBuilder that I just don't see?