I live in Denver and I need to replace two residential GFA furnaces, one 70,000 Btu and one 110,000 Btu. I have two estimates, one for Maytag and one for Amana variable speed two-stage units. Maytag warranty is 10 yrs P&L, Amana 5 yrs parts. Big price difference -- is the Maytag worth 20% more $$? Should I insist on another brand, or pass on either of these brands? Where can I go for reviews or recommendations?