Ive used both the mtroniks and moped and i would say go with the mtroniks
The 3 mopeds i had let out the smoke a month later
i have used an mtroniks Viper Dash for about a year without problems used a few months in my 12 scale with 9-10 turn motors and now being used in my stock touring car
I have also been using the mtroniks Viper Tempo11 in my minis with no probs