Seriously, the thinner faces and higher ball speeds possible using chromoly in a one piece forged head has my complete attention as a materials geek. And, the feel and flight off of them is pretty amazing.
I have looked at their online fitting tool a bunch of times and it always comes down to MP-20 HMB or JPX 921 HMP. There are 2 others that they would recommend as well but it depends on what you are looking for. I think if I had to choose blindly without a fitting I would go with the MP-20 HMB. But realistically I would get a fitting done to make a decision.