As far as aerodynamics go, most would probably agree that the P3 is the most aerodynamic of the three. Cervelo does things right, and the P3 is one of the best tri bikes you'll find anywhere. And their customer service is also top of the line. The others, however, are good as well. This has become a bit of a cliche on this forum, but fit should determine which bike you buy. You're probably not going to see much in the way of a performance benefit from the P3 over any of the others. I don't really buy all that stuff about one bike being "faster" than another bike. What makes a bike fast is the rider, but that rider must be set up correctly on the bike in order to achieve the performance benefits. So go get measured and fitted from a reputable fitter and then make your choice based on what he recommends. It may not even be one of the bikes you mentioned. But you will enjoy your new steed much more if it fits properly.

RP