Coincidentally, I uninstalled Office 2008 last night. I had both 2004 and 2008 on my Macbook, and I didn't mind 2008 too much as it didn't cause my fans to go into jet engine mode. It is full of bugs however (spaces anyone?), and MOST importantly (for me) it doesn't work with Endnote (bibliography software). It also stopped my copy of Word 2004 working with Endnote too. It had to go. I use iWork most of the time now, and use Word 2004 to insert references.
I think when it is finished it'll be a good suite (as others have said excel>numbers), but until it is fixed, no thanks...
If you insert references at later stage, then try Papers from mekentosj people. Papers is an excellent or shall I say gold standard app. It like itunes for pdf. Now they have implemented (although not direct as endnote) inserting references. It still uses endnote to create library but it does pretty much you do right now with the added benefit of whole pdf library in one place. Endnote sucks when it comes to reading through articles.