Maybe. We only bought 5 because we were receiving a few files in that version and were feeling bad about constantly telling people to save it back to 4. There were a few nice touches introduced in 5, but not enough to make me want to upgrade.
Quark 7 may be different though. Transparency alone turns it into a completely different animal; it's a feature people will want to have. My only concern is how it will print. To be fair, Quark is usually one of the most reliable packages when it comes to postscript printing, whatever other failings it might have, and I believe non-postscript printers are going to be taken care of properly in this release (at last!). As far as I can remember, it flattens PDFs by default, so transparency should not be a problem with RIPs.
But, yeah, I'd rather see someone else get it working first, especially as I rely on a particular third-party XTension.