Those all depend on what you need it to do. If you need to pull a light trailer, then you want the 6 cylinder, which also has a factory installed hitch. If you live in an area where there's snow or you take a lot of back roads, then you want the AWD. If you just want to drive it to work and around town but don't need to tow anything or go through snow, then the V6 with FWD will do the job, and will also be the best on fuel economy of the four options.
For the differences, if you can't see what I mean, the FWD is the front wheels powering the vehicle. AWD means all the wheels power it, but this is on demand, and not full time driving unless you leave it on, which is not good for your vehicle (worse fuel economy, more tire wear). The 6 cylinder (V6) just has more power than the V4. If you test drive one, you will feel that the V6 is peppier on the pedal than the 4.
