> If you would like to see it for yourself, please run JEdit on a system
> with 256MB RAM while editing several files of several megabytes each.
I would like to, but unfortunately systems with 256MB of RAM are no longer manufactured or sold.
> is one application I know I experienced problems with while Emacs and vi
> never acted funny.
Ironically, emacs actually implements its own garbage collector, which is based on mark-and-sweep. So apparently even on your ancient 256 MB machine, old-fashioned stop-the-world GC is fast enough that you don't notice it. As a side note, it's a little strange to see emacs held up as a shining example of efficient programming. The sarcastic joke in the past was that emacs stood for "eight megs and constantly swapping." Somehow that doesn't seem like such a good punchine any more, though. :)
The bottom line is that well-implemented garbage collection has its place on modern systems.