Having used both device since first month of release, I have to say the N900 just beats the N97 in every way. Never in my entire life have I had a device that is as close to perfection as the N900.
BUT... I do gotta admit, there is no device in the ENTIRE planet that is sexier than the Nokia N97. I used to love tilting it open and closing it back... I would have it opened sitting on a desk and everybody walking past by it would look at it