CyanogenMod 7.1.0 is running without issue on my original SF bought in CH. It's slightly behind the core Android firmware used in Swedish Snow (2.3.4 vs 2.3.5), although the new 7.2 Release Candidate is out now.
Had to upgrade the device to a 'Gen2' (which voids your warranty) using another bit of software, but this worked fine.
Note that using the 'Clockwork' ROM manager you can backup, install and try out any rom and if you don't like, restore your phone to the original or to your favourite one. I've done this a few times and not had an issue.
Instructions for Cyanogen 7.1.0
here.