I own the SmartQ7, if the N900, hell even the N810, would be in a 7inch version, it would be perfect: now the only advantage is the size (and you can buy multiple items for the same price).
I only use the Q7 when I realy want a bigger screen while typing documents - with abiword, open office was already slow on my N810. And Q7 ia much slower - but I won't complain, cause I know what I paid for it.
Well, let's say, the SmartQ7 ain't clever, where the N900 is: but it's cheap and has a nice bigger screen. I'd love to see a 7 inch N900-pad, with a slider keyboard: I would be so happy; I wouldn't even need the phone-part.