Losi & 808: Very agile cars that border on twitchy for many people. Like to drive on the edge, but they have a fine line before going over the edge.
RC8: Stable but yet tons of steering. Not nearly as edgey or twitchy as the Losi & 808, not also not as stable as the Mugen.
MBX-6: Very stable planted car, but at the expense of steering. Very easy to drive & very consistent car, but I would say it is harder to drive as fast as the RC8/Losi/808 will go but it will be easier to put down much more consistent laps.
Personally, I drive the 808 as I can't stand to drive a car that lacks on steering, I would rather only move the steering wheel a little than to bang it back and forth figuring out how to get the car to turn.