RE: E-maxx or E-savage
You have to realize that not too many people have used both. Of course, whoever owns that particular truck will vouch for their truck. I don't have an Emaxx, but I do own an E-Savage and I'd be glad to tell you my experiences with it.
The E-savage has plenty of speed. I've jumped it 4ft in the air only to land straight on its nose on concrete and nothing broke. I've accidentally drove into plenty of things (parked cars, trees, and even broke a water pipe w/ the Esav). And I'm still using the same parts from when it was new.
As for the diffs, that problems is over-hyped. It may have been an issue when the Esav first came out, but the newer stock has hardened gears. I haven't had any diff issues. The only problem I've had is a clicking noise. I opened everything up and nothing was broken or chipped. I'm pretty sure it's the pinion gear and ring gear, which can easily be solved with shimming the ring gear. I haven't got around to shimming yet. It's not a big deal to me because my Esav performs the same as when it was new. It only clicks at low speed.
I was also stuck between the Esav and Emaxx. Price is definitely one of the things that won me over. I paid $225 shipped for mine (Tower + $50 off coupon).