I've been an N800 user for about 2.5 years and have had my N900 for about 2.5 weeks. I've not had any issues with mine so far, (no reboots, no need to reflash, no extras-testing/devel brickage) and I'm still well within the honeymoon period, which I expect will last at least a year

That said, you will have read about the problems other's are having, so at the moment it seems a bit like a QA lottery (although I wouldn't like to guess as to what the probabilities are in terms of getting a good or bad device). There are bugs, for sure, but I assume you're accustomed to those.

My major concern prior to getting the N900 was that the screen would be too small. I handled one twice in Nokia shops, and then had reservations about the size, feel (heft, materials, etc.) and the usability of the keyboard.

However, all that changed after mine turned up. Not once in the last two weeks has the thought crossed my mind that the screen is too small, and my fingers have got used to working with the keyboard.

I can't really comment on your specific use cases, but thought you might appreciate the perspective of another long time user who's switched to the N900.