IMHO Jbuilder 9 is the best IDE, for me is lighter
than the others in your list. Has useful tools for
develop struts and don't require a lot of memory (my
pc was PIII the first time I used it).
Visual Age has been deprecated for IBM and Sun One,
Netbeans were a little slow to me.
It's a pity that Jbuilder is expenseve.
I heard Eclipse its a very good free IDE.