There are other options in 4wd. If you want, you can build your own TC3-O. It is a conversion you can buy that will convert a TC3 into an offroad vehicle and I heard it works pretty good.
Also, a conversion for the XX-4 is coming out that will change it to a single belt drive. This should correct the main problem with the XX-4s. Most people seem to prefer the handling of the XX-4 than the XXX-4 in the rough sections.
A dark horse vehicle that I am looking at is the Academy SB Sport Buggy. This buggy goes for $199 direct from MRC. Talking to the guys in Europe who are running it, it is pretty durable and a competent racer. If MRC really promotes this buggy and gets shops to carry the parts, they could have a winner.
I get lots of different views on the Yokomo buggy, some good, some bad.
As for the BJ4x4, looks great, but most likely will be priced very high ( $500 dollars ). To me a vehicle has to match the cost of the XXX-4 GP to have a chance.