I have both trucks, except older models than the ones you are asking about.

I have a Savage .25, and a .21 MGT.

The savage differentials are fine as long as you dont go to a .28/.30 LRP or Picco. Just keep an eye on them and shim them when they get loose and they will last a long time.

I have about 4 gallons on my savage differentials and not a hiccup. I also run an Axial .28 in it. I havent broken anything at all on it yet. Its really an awesome truck. It jumps great and is extremely durable. Seems to be lighter than the MGT, and makes a little better use of the power since it doesent have reverse. I like the design of the chassis better since it seems a little more ridgid, and it really is the most durable MT i have had. It is a little tougher to work on, but i dont really mind it. Its a blast to drive.

I havent had my MGT as long, and i have no idea how many gallons are on the truck all together. I am running the .25 out of my savage in it, and it has been great so far. There are several things that make it more user friendly than the savage. You can change the spur gear without removing anything. The savage require pulling the top of the transmission housing off(if its an X) and a Pre-X requires removing the engine. You can also change the clutch bell without removing the engine. On any savage you will have to remove the engine. The MGT also handles better, and brakes better. It has a flat chassis layout which makes it easier to work on. The transmission is fine if you keep the drive cup wear to a minimum. Slack in the driveline kills the transmissions from what i have heard. No problems with mine so far. This truck has also been durable for me. No problems yet, and it is a lot of fun to drive.

Id have to say if i were choosing new, I would take the 4.6 savage. I just really like the savage, but just pick the truck you like best and go with it. I wouldnt want to give up either one of mine[8D]

Eric