The N810 is a "scab edge" device, just behind the bleeding edge, where the blood has dried.
As mentioned if you are willing to:
Get your hands dirty - great apps
or
Suffer with the limited existing Nokia apps.
It's a great device.

The main disappointment I've found is the slow introduction of 16Gb microsdhc cards. I've two 4Gb cards filled and one dedicated to boot from mmc.

The Wimax version which is coming out will suffer from limited geographic usability, primarily Baltimore and Washington DC.

Because of the rapid software development there is a lot of "beta" that is very useful, but may never get finished because someone else does it better.