Please judge for yourself:
11lbs Truggy with Neu 1512/2Y (1400kv) with 10s1p A123 geared 1:16,8:
clip1,
clip2,
clip3
Same Truggy with Neu 1515/2Y (1100kv) with 10s1p A123 geared 1:12,13:
clip1
From my point of view. i had fun with the Neu 1512 and now with the Neu 1515. Both are capable to push a heavy truggy with authority. Both motors can wheelie a heavy center diff driven truggy. But you can gear the Neu 1515 taller to reach higher speeds and it will stay somewhat cooler. Going from mid speed to top speed feels more powerfull with the Neu 1515. I had power peaks up to 2.5Kw with both motors.
I have another battery set which makes the car by far more controllable, as it's only able to provide up to 1,4KW. Top speed is the same, but acceleration is more reasonable. A weaker battery might be an option.
As strange as it may sound but if i gear my Neu 1515 setup down to 1:14,56 it will not wheelie as much either. Maybe because tire ballooning is not as high as with the 1:1213 gearing.