What is your overall objective? How long do you plan to stay in the home? How much time do you spend in the home? Do you work on a schedule, etc? The more time you spend in the home, the longer you are going to live there, etc. helps to dictate the practicality of what you purchase. The Carrier Infinity System has been absolutely excellent for us, and our customers have absolutely loved them. I have all of the Infinity equipment out there in operation (Infinity 16, 19 heat pumps, Infinity 21, Infinity 17, 38TDB's, etc) and they have all been awesome, with hardly any issues at all! I guess to answer your questions about heat pump or dual fuel, that would boil down to the energy costs in your area. I feel the best bang for the buck in the infinity line is the Infinity 16 heat pump and the Infinity 17 A/C coupled with the Infinity 96 furnace. I have installed a few Infinity FE4A fan coils with electric heat and have not had any problems with them either. I'm partial to dual fuel or standard gas furnace with A/C personally. We also sell Lennox, and they also make a great product, but I feel on the high end equipment, Carrier has the edge right now. My technicians would testify to the same beliefs and we sell both every week. The Lennox is a good solid choice in the single stage market with their XC15 and G51. Take your time. I do not sell Trane currently, but feel they also make excellent products. If you stay with one of the "Big Three" You'll be fine.