I really like the keyboard, it's useful for writing emails, and a lot better than using a touch screen (like the ipod touch). People who haven't seen the n810 are blown away by the flip down keyboard.
Yes the keys are close together, but that's the compromise between form and function. I get a few typos, but i have sausage fingers (i'm sure I'd get more with a touch screen)
I do agree that the navigation key should be on the main unit, but I barely use it anyway.