Don't waste your money. There have been documented bugs within Quark that not only bloat the files it creates but also corrupts them. The shortcuts have changed in some of the most basic commands (such as "Save as" is NOT Command-shift-s, that command does "Add a faux shadow to the text")
On top of the very expensive price, you don't have service, I have heard a few posts about how when they try to call quarks hotline, nobody answers. I say, go with InDesign CS, infact, for the same price you can get QuarkXPress, you can get the whole Creative Suite from Adobe which includes Acrobat Pro, InDesign, Photoshop, Illustrator, GoLive, and VersionCue.
But other then hearing what people say here, go to a fellow designers who has Quark and ask if you could tet it out. I dare you to compare the two, InDesign and Quark do a 5 page document using placeholder text and stock images. Test out their PSD importing options, exporting to PDF, Typography control, Opentype compatibility, transparancy and colour managing, and you decide which one you would prefer.
p.s. quark has little to none of those items on the list where InDesign has leading edge controls.
Good Luck.