Toango, I think it's because you have a high torque version for the ebikekit gear motor (it can only go up to 20 mph) and a high speed version of the Mac motor (7T at 27 mph).
If both motor would have the same top speed for the same voltage (same winding), I believe the mac would have better acceleration because it's bigger.
ps: That makes me think I'd probably need to buy a 8T mac motor for good acceleration (rather than a 6 or 7T.) because you don't see that much acceleration on a 7T.
pps: On my brompton, I have a top speed of 30 mph on 74V8AH lipo. But the problem is that on acceleration I'm using sooo much watt, around 2500W. (crazy for a little 4.6kg motor
). I think I need a higher torque motor to increase the efficiency