I'm running the 1515 1y on 6s 22/65T on a 3905 emaxx and I like it. Granted I can't speak for the long term reliability but now my motor temps are cooler than with 5s & 4s and it's ridiculously fast and lots of torque.
Hmmmm, interesting. Any other experiences you can share? I can also buy a pair of 2S1P 5000 and wire each of them in series with the 3S for a 5S setup.