I have two friends who have tried them.
both have gone back to gas utv's, one a Rhino, one a Ranger.

Their issue was range. Four to five miles was all they could ever get. Bad Boy was very good to work on them, replace batteries, even replaced one of the buggies, but they just couldn't get the range to anything near acceptable.

Winch brackets broke on both the first time used and had to be strenghtened.