I haven't used the Festool, but from my own experience with the
top-handle and everything I've ever read about jigsaws, the new Bosch
are top-of-the-line. Never heard anything bad about either brand,
other than Festool's high prices. There is a review in the Nov. issue
of Pop Woodworking that you can download from
http://www.popularwoodworking.com/features/tooltest.asp
This review gives the Festool the editor's choice, but this was before
the 1590/1 came out, and one of their main gripes with the 1584 was the
tool change, which was updated with the 1590/1 saws.
Unless you really want the removeable cord on the Festool, I can't
imagine you'd be disappointed with either of these tools (read lots of
previous posts here on the 1590/1591), so why not save the C-note and
go with the Bosch... Check coastaltool.com for a good deal on the 1591.
No affiliation blah blah blah.
Andy