I would say get a Revo, for a few reasons, first off, you are familiar with Traxxas products, and obviously parts support is around. secondly, anyone can take a revo and race it well. THe revo has plenty of uumph to do back flips. If you are going to bash, The Tmaxx is also a good truck. I even race mine, but it has a TON of upgrades. The T-Maxx is, or was, the best selling monster truck, for 11+ years. They are not super weak, the only time I really broke anything on mine was when I hit stuff that I shouldn't have. There is a guy that races a savage, and when he is on, he is on, but it is not nearly as fast as my tmaxx, and I have a 6 gallon old stock 2.5. I think it is due to cornering ability over engine power cause he has a big engine in it. Everyone that I know that has a savage loves it cause they bash, and you can bash the savage hard and put her away wet. The LST2, have not seen many of these racing, I know alot of racers that won't get an LST2 because the LST left such a sour taste in thier mouth from constantly breaking stuff on thier LST for no apparent reason, other than it broke. Not to familiar with the MGT, but I have heard good stuff about it.
The Losi Trucks and the Savage and MGT are all big blocks, so that might be what you are looking for. The new Losi Aftershock is priced less expensively, but is supposed to be better than teh LST was, but I have yet to see one in action.
HTH
Rod