Got my phone more or less finalized on the Cognition 3.04 ROM now, very quick and battery life is decent.
Rockin' the full Nexus S clone theme if I want too, looks very cool but that live wallpaper sucks a lot of juice.
I'm not that into benchmarking my phone but after the Cognition went in, EXT4 lagfixes and misc. tweaks I was curious. I'm getting some very satisfactory scores on Quadrant.
I don't even need all that performance though, which means I'll be underclocking it to save some battery life.