I've been using the default n900 PDF Reader and had no problems with any ebooks, however, the application does not remember what page I last viewed when I reopen the ebook. I have to write down what page I was on which is an annoyance.

I just tried evince and it has a few nice things. I noticed loading the next page now happens almost instantly where as with the default reader, loading the next page would take around 4 seconds. Evince also remembers what page I was on which is the feature I want most. Evince however is not useable to me because as soon as I move about the page, I see multiple instances of the page content for several seconds before it settles down. I think I will go back to the default reader but like others here, I am saying the n900 community needs a decent PDF reader!