What's the difference between the galaxys2 and i9100 CyanogenMod builds? I own a Galaxy S 2 GT-I9100 so I'm somewhat confused what the correct build is for my phone.

The situation is particularly confusing since I want to try out CyanogenMod 10, which isn't listed in the available downloads for galaxys2. However, the downloads for i9100 list only downloads for CyanogenMod 10.

I currently have the 9.1-galaxys2 ROM running on my phone, so I'm somewhat certain that those builds work for my phone.

What's the difference between the two builds and how can I determine which is the right one for my phone?
There's no difference. The device was simply renamed within the build system between the release of CM9 and CM10, as the CyanogenMod Wiki page for the i9100 notes:


  This device used to be called galaxys2 on get.cm, so older builds of CM can still be found under that title.


So builds of CM9 (or earlier) will use the galaxys2 moniker, whereas builds from CM10 onward will use i9100.