After the mass amount of bashing on Lennox for the price of their parts, I've decided to go with Ruud/Rheem or Trane/American Standard. I'd like a 95% efficiency, 2-stage heat, variable speed motor furnace. Given that I have a proper install of each, could any of you make a comparison of the reliability, quietness, and any other categories you can think of between the XV95 and the Ruud RGRM?

Also, what's the advantages of a modulating furnace? I have no idea what it is. Are either of these furnaces a modulating furnace?

Last, I've seen that American Standard has a Modulating furnace and a 3-stage furnace. Are there Trane versions of these? Is a 3-stage furnace any more helpful or energu efficient than a 2-stage furnace?

I've been told a variable speed motor takes up the power of an incandescent light bulb. Is this true?