I was just using N810 on my Easter holiday and thinking should I upgrade to N900.

I still decided not to. The N810 for me is fine even if it lacks stuff like exchange syncing but because the N900 is a phone also, such things are not acceptable.

I currently use E61i + N810. I am planning to upgrade later this year to a device that would combine the good sides of both. One device I've been looking at is the HTC desire. The HTC HD2 would otherwise be cool but Winmo 6.5 is a dying platform.

The N900 was a real disappointment for me. I would gladly have upgraded if they made it as a tablet instead with bigger screen. Something like HTC HD2 but with a sliding QWERTY keyboard would have been cool!