My opinions on the keyboard.
It is small, but borderline from being too small. It takes some time to get used to especially since keys are awkwardly placed. The apostrophe/quotation key is inconveniently placed by the space bar so when typing "that's" will often result in hitting the enter key may times. I would say I have fairly large hands and coming from a macbook pro, I find the dell mini 9's keyboard usable, but not the best keyboard in the world.
The trackpad is quite small for me. Hitting the clickers and scrolling around does take some getting used to. Once in a while, I will have to use two hands to use it more comfortably. I think the ideal solution is to remove the buttons and have apple's click pad come to play. Is it impossible to use? No. Is it difficult and different for larger hands? Yes.