150 mph? How about 200 mph?
The offerings from Alcon, AP, and PFC will all improve brake feel because they are stiffer (aluminum makes that easier) and have modern piston/seal designs. An argument that one caliper has less "drag" than the other is a red herring: none of these calipers have measurable drag if properly installed and serviced. (Simple physics will allow you to quickly determine that if they did, pads wouldn't last long and we'd have problems with boiling fluid.)
Brakes get more important as the difference between straightaway and corner speed grows, downforce increases, and cars get heavier. In FF/FC/FB we don't slow much for most corners, don't make much downforce, and don't weigh very much. These cars just don't spend much time braking.
On the other hand, unsprung weight is important in braking, cornering, and acceleration. We spend a lot more time doing that! In fact, the only place where you could argue that unsprung weight isn't important is on the last part of the straightaway.
I believe that all else being equal, unsprung weight is the most important characteristic of a caliper for these cars. Every race car designer I know agrees.
Just for reference, a modern F1 caliper weighs...get this...3.5 lbs! And they are made from aluminum, not some exotic MMC material. A modern four-piston F3 caliper weighs just 2.6 lbs. If they were legal, we'd be running our four-piston caliper design that runs 2.2 lbs.
For what it's worth.
Nathan