whatever phone you buy, android is android, and the custom roms features the offer are the same. depending on whats working. s2 is very lucky to have camera working in aosp roms, some device dont (galaxy tabs, some xperia).

its always cm, aokp, paranoid...these 3.
their custom aosp features, if you've been an avid rom flasher for 1 or 2 months,
then you've see EVERYTHING. there is nothing ground breakingly new for a long time.
the usual stuff like volume button skip track,notification toggles,weather in lockscreen, on screen nav bar (customizable), bln, shortcut in lockscreen, slide notification brightness control, dpi per app change, etc etc....the usual stuff.

all these features comes at a cost, which are some bugs & restriction (no fm radio, no hdmi, fail wifi direct, volume bug,ringtone reset, random reboot, sod, certain system app issue, ah you know the rest)

you want the best combined aosp features, there's jellybam that combines everything.
it will never reach stable version, it will keep play around with numerous buggy release to attact more donators.
the stable version tag will be slapped on the last working release when next android version release
if you dislike bugs and hardware compromised use stock rom, but sacrifice alot of custom aosp features

the way i see it, the perfect rom for s2 will be either:
~stock samsung rom that has all custom aosp features similar to jellybam
~or custom aosp rom that has all working hardware (hwc, wifi direct, hdmi, fm radio)

neither of this will ever happen. so just choose one side.