It all depends on what you are doing with the car. A street car has no use for aluminum heads, and a strip car has no use for steel heads. If it is a bit of both then it depends on how fat your wallet is and if you know a good head builder that does a good job for a good price. I have priced valve jobs on steel heads lately and it is getting expensive!
The funny thing about science is that if you change one miniscule parameter you change the entire outcome to the way you want it.
