Typing this on a late 2010 MBP running 11.10. I started on 10.10 which needed modules and other bits from the mactel PPA for audio, backlight control, hotkeys etc to work properly. 11.04 was pretty good - just needed a wireless driver from the backports repository I think. 11.10 so far is working with the exception of 3-finger tap to middle-click in Unity. I've switched to KDE which is good enough, after some theming/tweaking.
From my sample of 1 I'd say Ubuntu Mac/Macbook support is good about 6-9 months after the first release by Apple. Before then it's hunting around forums, and PPAs.
