After I9100G entered the nightly stage some time ago, the I9100 has followed suit and is now in the nightlies stage too. While I haven’t tried it yet (still using Galaxy Ace at the moment), I have followed the XDA thread and by all accounts, it is mostly working fine (except for RIL crashes and some memory leak). Going through the thread may be daunting (at last count, it stood at 1121 pages long) but here’s the basic summary:
RIL crashes may occur. Try GetRil app from Google Play Store. Matching RIL may help to reduce or eliminate this.
Memory leak may still occur. Rebooting your phone every now and then when the memory gets low is the only thing to do right now.
Last but not least, CM10 does not have Jelly Bean’s Hardware Composer (HWC for short), it is using the Ice Cream Sandwich HWC which makes Project Butter not working everywhere. This sparked a debate on whether HWC is broken or not since the ICS HWC is present and working but the JB HWC is not. My take on this, ignore all posts regarding HWC and just remember that JB HWC is not yet present and will not be present until Samsung releases the JB sources for S2. Maybe the JB sources for S3 may work. Wait and see.
Take note that starting CM10, the device name is now i9100 as opposed to galaxys2 previously.