Lets confirm/Deny/Rebutt Some things

The processor is the same speed.
The n800 was underclocked to save bettery life . Now that they have improved os support, they can bump the clock speed back up to the original 400mhz without affecting battery life. That means your n800 should be running at 400mhz when you update to 2008.

Not Either OR
You dont have to buy an n810. And it looks like the n800 has already dropped to 250 and will probably drop to an even $200. If it supports all the same software but is cheaper and doesn't have a keyboard, what is the complaint!!!
This is not the same as the transition from 770 to 810. They will both support the same software.Moreover I think Nokia learned there lesson with this model, they want the software to be ported quickly, and that can only happen if there are developers with devices.

Way better case
so far all the reviews have stated the case is much better than the N800 case.

Keyboard is a big improvement
The n810 is actually thinner than the n800 even with the new keyboard.
The directional button had to be placed with the keyboard so that you can use it and the keyboard without straining your wrist. The only other option for nokia would be to have two buttons, one on the keyboard and one on the display.

As far as I am concerned this is a great device. And I am sure to go out and get an n800 now that they reasonably priced.