How do I compare furnace models?
I believe it is best to purchase a level of unit that meets the needs of the home.  80% single stage is good for basic heat where the fuel is not too expensive and the climate is not too cold.  More sophisticated technology has higher initial costs and repair costs, so it is not advantageous to go up the efficiency scale unless justified by the fuel savings.  The quiet operation and more even heat distribution that comes with a variable speed 2 stage unit is loved by some homeowners, but again that adds complexity and cost.  Also, 2 stage variable speed does not save much in operating costs.  If one is not sensitive to cost and one wants to buy something fancy to show to the neighbors, I see no fault in that.

I would also say that correct sizing of the unit, correct installation, and a reliable contractor are all much more important than brand.