With my Galaxy S2 abandoned at Android 4.1.2 by both Samsung and T-Mobile, and performance starting to deteriorate, I decided it was time to bite the bullet and head into the world of custom ROMs. Decided to go with CyanogenMod because of their new simple installer.
Ran the Windows installer, connected the phone and after a few butt-clenching moments, the phone was booting into CM10.2 (Android 4.3.1).
It's a little different, but so far seems to be working pretty well. Feels faster and more responsive, but that could just be from having a freshly wiped device. Will see how things go as I proceed with reinstalling apps and rearranging the screens to the way I like them.