I've had mine for 2 years now and never had a problem with mileage - 15/18. I use it a lot in the woods and never had a problem on or off road. I do agree the tires are too small for the truck (that was the very first thought when I saw it). But it's been a good truck that handled well on a WA to NJ road trip of 4000+ miles with a motorcycle and stuff in the bed ranging from twisting turning roads in Yellowstone to 90+ MPH straightaways in SD (milage goes to 14-15 at 90MPH).
Engine - Powerful and quiet. I constantly get comments on how quiet it is. I also like the 40/60 split rear seat.