I test drove the X8 4x4 wheelchair by MagicMobility. They are the same company that makes the MWD V6 offroad chair. So I'm going to keep this simple. I test drove it around the biggest stock show in the USA and around my hunting lease. Conditions ranged from pavement to turf to slick mud and water.
Pros:
1) It went anywhere I drove it (even up a slick, muddy, and steep hill.)
2) It absorbs most of the shock (probably the tires) you would normally experience in your everyday chair.
3) The batteries lasted a long time. I put two heavy days of driving on this thing before recharging and it was only down to a little over half.
Cons:
1) Driving in tight quarters and in reverse is very difficult. The chair operates similar to an RC racecar but you control everything with one joystick instead of two. (Moving forward is a cinch though!)
2) No Mud flaps! Before I even got into any heavy mud I noticed that there was already mud splatters all over the fenders.
3) It's huge! Although it will fit in a minivan, it takes a lot of back and forth to make it go. (And possibly some damaged interior)
The steering mechanism, although difficult/different to operate, is effective. With a motor on each wheel and small actuators used to steer the front wheels a single joystick controls all of this. There were a few times when I was first starting out that I wished I had and second stick to control the steering.
Overall it is a good chair. It can do what it's made for.