The Savage is definitely tough, and quick.

The Maxx will be an arguably better vehicle (Keyword: Arguably!) once it's had a couple of it's weakpoints upgraded (Plastic Rear Diff Case and Skidplates, I'm looking at you!)

For Nitro, I think a bunch of folks have complained about the older TRX engines, but I've been out of Nitro for a long time, not sure there.

Depends on what you want out of the thing, ultimately. There are bombproof Savages and T-Maxx's, and they both take about the same amount of money to get to that point.

What you should ultimately do, is go to your LHS and see what they carry more of, because when you break something, that's what matters. If they carry more HPI then Traxxas, go Savage. More Traxxas? Go Maxx.

PERSONALLY, I'd get the Maxx, but I enjoy the tinkering. Nuke-proof once you get the fiddly bugs worked out.