First of all, you don't give the sizing of furnace and AC condensers quoted.. Repost.

As to Lennox, it is a distant third in the top tier HVAC brands. One and two being Carrier and Trane and their sister companies Bryant and Am Std. And yes, they think highly of their product.

I don't know enough about Maytag other than to say they are part of the appliance brand HVAC companies marketed by parent Nordyne. For the most part the HVAC is identical across the various companies.

As to Amana, it is cosidered to be the premium brand to parent Goodman. You should note this dealer is quoting a Distinctions furnace which is a rebadged Goodman. I don't care for that furnace. I would want a true Amana furnace. What efficiency are you looking for? Lennox dealer quoted a two stage var speed 80% model. You might look at one of these Amana furnace models.
80% AFUE AMVC8 / ADVC8,
80% AFUE AMEH8

What size HVAC are you replacing?

Post back.

IMO