Least we forget that the Powell Phantom 7 is a MAN size ride and not something with a Chinese fake out of a Honda. Give me a Briggs & Stratton or a Tecumseh. But I am old old school and soon to be older yet. I was a Powell dealer and they weren't bough to put under the Christmas tree.
Tough question considering some here consider anything larger than a 6" wheel mini is a minibike or mini bike as some call them. Minicycles is what they call an 8" or larger bike which to me seemed stupid it should have included 8" wheel bikes like the Murray and some others like the Thundebird. So if we're talking anything goes wheel size the best would have been the Steens small Hodaka powered motorcycle with the Ceriani forks and shocks and Rickman Metisse handlebars. Now if we're talking 6" wheel or smaller the Cat Endura or any of the 6" wheel swingarm bikes with angled enging plates and jackshafts and TAVs. A tough question to narrow down really.
from what I've seen at mini bike events the bikes with larger wider tires always seem to do the best off road, and off trail. they seem to be more stable and have better traction on loose surfaces they don't slip and slide as much as the narrow small tire bikes. I've never driven a wide tire bike so that's just the impression I have from seeing their performance.
Ok if the wheel size is you say is what makes a good off road bike. How and where does the Rokon Trailbreaker fit in. Small engine and big wheels and gearing for climbing the big big hills be it rocky or just sand that machine does it all. And it even floats. I sold that machine why I don't know just had too many to ride I guess.
I really thought the bigger bikes would be more fun offroad, but I suppose it really depends on the terrain. I rode my Hilltopper on the trails at Windber this past summer. It wasn't bad, but in wet stuff it had absolutely no grip. The TAV really helped grab and climb but the sideways sliding was awful. The Super Broncs are so big that handling them is a real chore on trails.
However, in open fields or flat terrain with little to no curves or turns -- sure, the big tire bikes are great. Nice and comfy on the ole spine. I've heard the Powells are great on trails. With the narrow wheels and the improved suspension, I would tend to believe it.
I just watched the video of the MB200 I wasn't impressed sure it was fast enough out on a flat trail through the grass. Where is the dirt hill with rocks and a little canyon to ride in to me that's off road. It always was a wonder to me that the minuet you buy a bike car or truck you must do some MODS too so called make it yours. If you need to make more power or top speed is it the engines fault or the gearing to match the riders weight.