It was over 25 years ago that that I had that bike but it seems to me that the Rocket does hook up better. If I remember correctly the Magna was rated at 114 hp and the Sabre at 121 hp. I do know that back tires didn't last long at all and I never did find one that would hook up.
I do enjoy the torque - BUT - to me it's start to finish time, speed and top speed.
My Ninja (after slotting cam drives and degreeing in lobe centers and some carb and head work) would bury the 180 mph speedo.
My R3R won't crack 130 mph.