Well, I have been using the MGM TMM 25035 8S Car controller for a while now and thought I would post a mini review. In the past, I have recommended staying away from MGM ESC's and have even posted some negatives.
I have to eat some crow and change my tune. The new E-series with the V6.32 firmware are fantastic. I have been running mine in a Savage Flux with a Neu 1521 1Y motor-using 6S and 8S packs. The 1521 is a real current hog, especially on 6S. The MGM stays warm, just warm, to the touch no matter how hard I drive it. And this is with no fans, just the external heatsinks. Even gearing up to 25/44 with Cen diffs, I can't get it to thermal. The old bizarre braking/reverse quirks are gone. Everything is smooth as can be with no strange behavior. Proportional braking and reverse work great and can be adjusted in software from a PC USB connection.
PRO's
1. Bullet proof-cool running, smooth running
2. PC USB and field card parameters programmable. Works flawlessly.
3. USB firmware updatability. Burn new firmware from the web.
4. Records max currents and RPM's and stores them in the ESC. You can hook up to your PC and see what amps you pulled on your last run.
5. No fans and still stays cool. 250A continuous, 300A for 5 seconds.
6. ESC's with car software up to 15S, yes 15S!
7. Fully customizable Lipo and A123 cutoff voltages.
CON's
1. No BEC, Opto only.
2. Expensive-my 8S was about $410
3. Have to send to official dealer in Canada (Icare-rc.com) for repairs. (Still better than sending to the Czech Republic!)

All in all, an impressive ESC. If you need over 6S and don't want to wait for Castle's HV Monster, then definitely give one of these a shot.