mmm or tekin rx8

[nitrostarter]

6s X 4.2V(fully charged)= 25.2

Same rating with the Tekin.

As far as which is better, it depends on your application. The MMM has been out for a while and is a tried and trued system. Tekin is just getting mainstream with their system and people are thoroughly testing them.
Another point is that the Tekin system has the option to run the motor sensored or not. The MMM is strictly sensorless, but new updates on firmware and software have smoothened out the MMM's acceleration.
There are lots of programmable features about both systems, +'s and -'s, take your pick and try one out.