From what I have heard the Eee 901 and 1000 currently have a few driver issues with Linux (largely due to the wireless drivers). This is what has stopped me from putting Linux on mine. Then again, I lack confidence slightly in my Linux skills. From what I've read on the net if you are reasonably proficient there shoudn't be any issues. The Eee also has a huge user base, and Linux developments are happening pretty fast among a number of distros.
Aside from that, I am so impressed with mine. The two reasons I got my 901 over a Wind were the SSD, which is far more rugged, and boots Windows rapidly, and the multitouch pad, which is in my opinion the best thing to ever happen to laptops! I honestly can't do without it on a laptop now!!!