Speaking only from my personal experience, after two trips.
Kia Sorento tows our K-Z Classic 16BH very well. This trailer is only 2700 lbs gross weight, but since Kia can't take much tongue weight, I don't think it could handle much bigger trailer. The small trailer though, tows very well. You obviously notice the weight when accelerating and notice the "2 sheets of plywood effect" when driving into headwind, but I don't find it too bad. Average fuel consumption has been 15-16L/100 km while towing, so almost double vs. non-towing.
Having said all that, I wouldn't want to tow 4000 lbs trailer with Sorento.