Mac User UK (13th March issue) did a comparison review of Quark 8 versus InDesign CS4.
"The question of which to buy is a tricky one. Certainly, XPress 8 will
give the Adobe team something to worry about for their next release –
but it's about time they had some real competition….There are now fewer reasons for Quark users to
make the transition to switch to InDesign, although it's unlikely many
users will make the transition the other way."
IMHO this seems to be a neat summary of the state of play. It's good to have competition in DTP. Mac User had more than a few criticisms to make about the Quark 8 clunky interface (no surprise). Also it states that InDesign CS4 is not a big upgrade, so CS3 users may want to stay put.
I don't think the full review is on the Mac User site, but I have a scan of the article from the magazine that I can email to anyone who wants it,. Just drop me an email (see my About Me page for email address).
Which is the most talked about DTP package on the blogs – it's "Quark (in Blue)" Versus "InDesign (Red)"