If you want an easy swap you should decide between the CBX and dohc 750f calipers. The CBX calipers have a rather large single piston that will provide strong stopping power. The dohc 750f ones have two smaller pistons that will provide less fade than a single piston as well as increased braking. As to which will provide better performance, I'm not certain, I've yet to try either. I've got some dohc 750f calipers for my 78f but I won't be able to give any feedback for a long time, that bike isn't even in it's early stages of a build yet.
Other members may be able to provide you better, more concise information.