[Jeffy]

Pros:
Looks cool
Sturdy (depending on wall thickness)
normal tank drive pros

Cons:
Looks like alot of machining on the lower supports. Why do the machining on the lower, more load bearing, frame members, but not the upper?
Lots of welding to do also
Without the ability to slide the gearboxes, you will need another way to tension the chain.
Servo shifters have not been getting a good rep from what i have read. (no personal experience)