[EricH]

I forgot one other difference. It wasn't an issue the last couple of years, but it has been in the past, and that is traversing obstacles.

A 6WD will generally need somewhat more ground clearance than an 8WD to cross the same obstacle. This is because there is more space in between the wheels to get a "high-center", where the obstacle hits the frame and stops progress. Those aren't exactly fun to get out of, and often need a hit from a partner.