Well, I downloaded Docs to go premium, and I have to say so far it's not bad at all. The intergreation with Dropbox is great. I'm really enjoying the functionality of it, works great with Good Reader too.
I went with Quick Office after reading several reviews for it and D2G. Proper handling of footnotes wasn't available in either; that would have been the main factor for me. Since that wasn't an option and they were pretty similar, I bought QO when it was on sale.