I installed Ubuntu 9.10 on my Macbook (not a Pro, it's the 2009 13" model) last year and it worked fairly well. I had issues with kernel updates breaking my Broadcom (wireless) drivers, which resulted on me moving to Sabayon Linux; it's been working beautifully on my Macbook ever since.
BTW, one of my friends runs Ubuntu 10.04 on his Pro and has never had an issue.
In answer to your question about features like multi-touch, it depends on the drivers and what the community pushes out. Two-fingered scroll/click works just fine in Sabayon and Ubuntu, but I don't know if there are any drivers which take advantage of the other swipe/gestures of the trackpad.