I am a huge fan of it, yes. Except for the major bug I discovered over the weekend that I'm waiting to hear back about!
Lots of very useful new features have been added (from my company's point of view at least), although there are also a bunch of new features that we won't be making use of at all. All in all (if inter-document links would actually work) it's going to save us a lot of time and therefore money. So I was happy to pay for an upgrade to Acrobat 6 Pro as well as a new full version for my business partner. (Of course, I haven't installed the upgrade yet - we'll be 5 on one computer at least until this bug is fixed!)
(And no, I don't work for them!)