Personally, I neither care about benchmark scores nor video playback so it doesn't much affect me. My last rom had it disabled by default, my current one has it enabled by default. I didn't, and don't plan to, change either.
Erm actually no stagefright working for h264 in a correctly configured ROM is not opinion, its fact just as 1+ 1 = 2 is fact. the popular opinion here appears to be the equivalent of 1 + 1 = monkey.
Stagefright having occasional issues with AAC and eACC quality from streamed media is also fact, but non relevant to any of the discussion here.
I dont believe it speeds up h264 decoding ,the fact is that stagefright makes it more flexible for a given HW configuration (check the google docs: fact).
You try to help people who are shooting themselves in the foot to point the gun away and they point it at you instead. No wonder funkimunk doesnt want his ROM on this place.