I have the 701 4G Surf (Linux), so it has (more or less) the same keyboard as the 901. It takes some getting used to, but I can use it pretty easily now without thinking about it much, and I'm a 90+ wpm touch typist. I go a little slower and I still miss shifts occasionally, but other than that it's fine.
Have traveled with it on two airplane trips and one long car trip. Worked a treat both times, picked up hotel Ethernet and wireless like a champ. I bought a plain stretch sleeve and put it through security in the sleeve with no problem. (I did take it out of the bag, just left in the sleeve in the tray.) I carry it with me daily in a small messenger bag for work on a train commute.
I like the 701 because it has the smallest charger, frankly. It's a wall-wart style and the prongs fold up into it. I had a Toshiba Portege R100 and while it was thin and light, it was still too big to throw in a bag that wasn't laptop-sized and the charger and auxiliary battery (necessary if you were going to use it more than 2 hours) weighed more than the laptop. It's a consideration for portability. I'd look into the extended battery.