I've played a fair amount with Pages, less with Numbers and none with Keynote. I do like Pages a fair amount. Unless you use Track Changes I don't see enough new stuff in there to really warrant an upgrade, though.
My big issue is that Pages doesn't support the standard ODF format. Now, I can understand why they didn't: ODF is new and, although it's an ISO standard, the number of ODF users is very small. Apple is a fraction of marketshare, ODF is a fraction of marketshare... why would Apple want to implement a feature that would only benefit a fraction of a fraction?
Now that my reasoning is out of the way, it's still frustrating because I believe that ODF is generally a Good Idea (tm), and that all data formats should be open and portable. In fact, I recently converted all of my .doc files to .odt files. So now that I realize that I kinda like Pages to the point that I might want to use it as my default word processor, I'd have to open all of my .odt files, convert them to .doc, then import them and save them out as .pages. Whew. If Apple didn't change the format up so much between versions, somebody could write a converter for NeoOffice (since Apple's pages format is XML-based).
Another issue is other people being able to view my Pages files. But honestly, I'd be deluding myself with images of ODF grandeur since almost nobody I know uses ODF and I'd have to convert it to something else anyway.
LOL, can you tell I'm struggling on the whole format issue?
All that said, from the perspective of a NeoOffice user, Pages is very much clean-and-sexy Mac native, high performance, and packs a lot of what most people need with very little of what they don't.