Are the 5.0L models better than the V6 models? Anyone?
Yes, Absolutey, without question, they are superior. They have a better engine design, no "tensioner" issues, actually this engine/transmission combination was pulled from the F150. Its designed to be used in a much heavier truck, so the reliability is better.
Very very few problems reported with the 4R70W transmission bolted to the back of the 302, darn close to bulletproof for this application. The V6 has always had transmission problems inherent to the design.
Well known issues with all explorers/mountaineers are wheel bearing/hubs, front sway bar links, the occasional cvaxle as well as the upper/lower balljoints. All should be considered normal maintenance items.
The All Wheel Drive system (only available with the V8 engine. The V6 engines have the "torque-on-demand system) is a decent setup if maintained properly. If you get snow in the winter where you are, the V8 AWD truck will drive like it is on rails in the snow, even as much as a foot of it.
You can not mix/match different tires on this truck as doing so will damage driveline components such as transfercase, front and rear differentials, cv axles and wheelbearings. You must replace all tires as a set.
The V6 models have the aforementioned torque-on-demand system. This setup uses the ABS sensors at each front wheel and one in the rear differential to "sense" wheel spin and automatically engage an electronic clutch to engage the front driveshaft. Known issues are if an ABS sensor takes a dump on you, you have no 4WD, if the electric "shift motor" mounted to the side of the transfercase also takes a dump on you it gives the same end result. Some have reported that this shift motor can also die leaving you inbetween 4WD and 2WD.
Fuel economy between the V6 and V8 models are nearly identical, so that is a non-issue. It is about 1 MPG difference.
If you find two explorers in the same condition for essentially the same price and one of them has the V8, get the V8 without a single doubt or hesitation.