I personally sell them (i'm a procomp dealer),i have to agree that the castinos look good. I too agree and have said the deck is thin, but that should not be an issue unless you put a bunch of nitrous or blower on them.
Some of the better engine builders and head porters have brought up issues with the valves and studs being out of location, i have not run across this issue on any set that i have sold that i know of.
What has been said about the rocker studs have thin material under them. Tying them together with a stud gurdle will not correct this problem, but if you keep the valve spring pressue low that might not be an issue. I will say that the flow rates are inflated, and the ones listed are the fully CNC ported heads.
I will not sell a set to someone who is running all out competition, but they are o'k in my opinion for the street or mild competition.
JMO
Zip.