My opinion ( I have an N810):
- keyboard is not very good (you have to press Fn for numbers) and the special characters are on different locations, so most times I use the onscreen keyboard with modified layout (4 rows incl separate digits row and predefined www. and .com).
- nice bright screen well readable in daylight
- there is only one memory card slot instead of 2 on the N800, the other is 'occupied' with 2GB internal MMC.