While the oldest the T-Maxx has the most after market Hop Ups available.
I have a Revo, original TMaxx and the 3.3 TMaxx and a Savage.
So for after market options: TMaxx wins by a LONG shot. No comparison. Carbon fiber, titanium, aluminum, etc.
Raw Power: Jato does it, but both others are close. With after market engine, the Savage can be a beast!
Ease of use: Still the Traxxas trucks. HPI is close, but Traxxas really has the RTR down.
Overall Value: In my opinion, its a T Maxx.
It is a solid platform, can be modded extensively, its tough durable, fast and is fun.