From a dyno/tuning, first-person-experience perspective, here's my opinion...
Most popular bang/buck on an average engine? The AFR heads. Which one? Depends on the displacement, cam, and intended use. Smaller ports work better in smaller rpm and smaller power ranges with smaller cams. There's more to the answer than just peak power unless it's all about the peak dyno number to you. For a 370+" SBF, I'd buy the 205's if it was my own engine and AFR was the best head available...which it isn't.
The best SBF head from a power perspective, is the new Jon Kaase SBF heads.
http://www.jonkaaseracingengines.com...aseJegsSBF.htm
For those of you that don't know Mr. Kaase's work, he's won various engine master challenges several years running. This head out performs anything I've seen to date; and I've seen all the above mentioned heads, as well as even some DOHC heads and even a set of rotary valve heads. These new heads from Kaase are incredible. I witnessed a 331" small block ford with a TFS intake and a cam designed by Hi-Tech Motorsports produce 414 rear wheel horsepower at 7200rpm measured on a dynojet 248 ON PUMP GAS with 28deg total advance, and a 13:1 Air/Fuel ratio, no power adders. It's a 10.3:1 CR engine. I've never seen that before. He recently swapped heads from a set of AFR 185s to these. It made 357rwhp with the AFRs...nearly 60rwhp less!