Questioning Gas Power/Torque vs Diesel

We bought our Era in Forest City, IA. After touring and putting the required 1K miles on it we pulled our Suzuki GV from Forest City, IA to Santa Fe, NM. The Era had no trouble pulling the Suzuki but it did seem to knock a few mpgs off the mileage. The only time I really noticed the Suzuki behind me was when I hit some bumps. It would yank on our Era pretty hard. It is pretty flat between Iowa and New Mexico so I can't really say how it tows in the mountains. We don't tow with the Era. The Era is a pleasure to drive in the mountains of northern New Mexico and Colorado. The Durango-Silverton-Ouray route was particularly beautiful in the Era. I am sold on diesel. I pass people going up long hills. They pass me when we go downhill.