Also what advantage does the variable 2-stage speed give versus the 2-stage speed furnaces

I don't think there's much between the three quotes you got. Go with the company you feel most comfortable with.

Do be mindful that HE furnace condensate drains can freeze in your location and this would cut off the furnace, leaving you with no heat. Make sure any condensate drains are run in an inside wall and not through an attic or crawlspace.

I am wondering if those are all the right size. You are saying you have a 90k btu now. None of the ones in your list have that much BTU, although all 3 have a better efficiency rating than what you have now.

We need to look at the BTU output of each furnace first to convert apples to apples.

Your original lennox furnace Btu output is 74,700. How did this furnace handle the coldest days? Was it able to keep up?

York - Btu output 57,,600 Confortmaker - Btu output 76,800 Lennox - Btu output 67,200

If your old furnace struggled on those coldest days the York and Lennox is not an option and undersized. In fact the York could be grossly undersized with a Btu output 17K less than the present furnace, and quite a large difference if the old one struggles even a little. In this case the Confortmaker would be the best option.

On the flip side if the old one has no problem and on those coldest days only runs a few minutes but often, and you get hot fast then cold, it's oversized and the lennox, or even the york would be the ones to considered, but I think the york is too small.

How did the salesman determine these furnace sizes? Did they do a load caculation? If the old furnace did Just OK the York salesman dropped the ball. York doesn't jump deep into cutting edge technology, and as always the more complicated with bells and whistles the more parts complicated parts there are to break, as seen in lennox.

All units are mid level units and not over engineered to the point of ridiculous confusion. Personally I'd choose the Confortmaker. It's made by International Comfort Products, a subsidiary of United Technologies (UTX) which includes the brands Arcoaire and Heil, and also the parent company of Carrier. I would compare UTX to GM which uses many interchangeable common parts in many of there models. Lennox international owns other brands I've never seen and common parts are rarely interchangeable and higher priced and would compare them to BMW.

Lifetime warranty is self explanatory.

@sktn77a yes all three have quoted to reduce my output venting lines to meet current day code

@outpaientzero the current furnace motor failed on me thus prompting this change to look for a new one. the sales folks all took into consideration the 1200 sq ft of my 3-storey home and then later on gave me the model numbers with the btu.

the unit itself has no issues and handled the -21C night very well but due to the age of the unit I am looking to change it out.

"@sktn77a yes all three have quoted to reduce my output venting lines to meet current day code "

I don't know that is a code issue. My furnace was installed to code, permitted and inspected, but the condensate line occasionally freezes and we have no heat on that floor! (and we're in North Carolina, not Alberta!)