They are all pretty much the same. More efficient/better performing simply costs more, no matter the brand.

The best is the one which is the appropriate for your house and climate. Can you provide some information about your house and location? The size and age of the house, near what major city, and what fuel you will use for heating. The other important thing is proper sizing and installation. You can buy the "best" equipment. but it will never operate correctly or efficiently if it is the wrong size or improperly installed. You will need to find a HVAC contractor who are confident will do things correctly, follow the building code, and will respond if their are problems in the future.

I'll add two additional considerations to mike_home's list: the lifestyle needs of the occupants, and the budget. The best system for any application is one that balances the lifestyle needs of the occupants, the design criteria for the particular location (code requirements,) the constraints of the particular home (size, layout, insulation, solar heat gain, air leakage, etc.) and the budget. When considering budget, keep in mind that you'll need to draw a balance between the initial cost of the system and the operating cost over its lifetime.

I had a Bosch system installed, replacing a Lennox system. My neighbor installed a Lennox system, replacing his old Lennox system. I haven't seen any Carrier or Trane systems around here. Bosch is relatively new to central air/heat pump systems.

We are both pleased with our decisions!