I would like to chip in here. I own an S2 and if you're talking about a 'stable' ICS ROM, then there are a plethora of those. Resurrection Remix, Slim ICS, Salman ICS and Rootbox ICS are jus the ones at the top of my head. All of these ROMs are stable and fully functional. If you're talking about Jellybean, the CM10 pre-alpha was released 5 days ago. In this short amount of time, 3-4 devs have already come up with 'fully functional' ROMs. I do not wish to take sides in the eternal iOS vs Android flame war, but people should seriously do their homework before talking out of their behinds.
AOSP based roms do not have fb contact sync + no fm radio + RIL issues have not fully been resolved + no smart dialling. AOKP is in simple words a kanged version of CM9, slower as well.
CM10 has hwdecoder still not fully functional apart from major mediaserver batteryhog issues. And the other roms are just copies or repo synced builds.
As a user I want my phone to work as in every feature to work.
Stock Sammy based roms are just 'deodexed, zipaligned, with either jkay or lidroid frameworks' with a font pack or new icons. That is AFAIK called cooking not developing and can be acheived by anyone who has the slightest amount of brains using dsixda's kitchen. Some of the amateur woek us even based of unsafe 4.04 Sammy roms.
Get your facts right before quoting examples.
Thw discussion us about what is available out of the box. If dev support was a major criterion for buying phones, the nexus series would have been massive sellers. They are not.