I just got to sit in the new Project X, and it looks sweet. I have been paddling a 2010 allstar at 5'9" 165. I am super excited to get the Project X with real thigh braces and outfitting! I like the Allstar, it is an amazing playboat, but I am not a fan of the outfitting or the stern. I am excited to have a little more stern on the Project X and a little more volume all around. The rock star looks cool, but the stern looks even smaller now and they haven't fixed the problem with the backband cutting into your side? I do like the raised seat, one less thing to customize to get more leverage!
I fit in both the Project X 48 and 56 comfortably. I like a little bigger boat usually so I am getting the 56, but you will probably want the 48 at 150? I don't really trust the gallon sizing between companies, it never seems to be right. Just from looking at the boats side by side it looks like the Project X 56 is between a superstar and an allstar, and the 48 is between a allstar and a star?
My suggestion is demo them all. We have open pools here in Jackson starting in Feb. to try out all of the new boats. Try to find a demo around you.