I tend to disagree,we have alot more humidity then HEAT,and if you live in a shaded lot or a 2 story home 2 speed is the way to go.Also if you want to zone it.
It's NOT the BRAND,it's the company that installs it!!!!!
Look at the sensible heat ratio of many 2 stage A/Cs. On low cool, not much latent capacity to them.
So it is better with a Humdity control thermostat to FIRE a 1 stage a/c unit than a 2 stage unit with a variable speed fan????
The answer is in the spec sheets, in many cases yes in some no. My point was that 14 or 17 seer units usually have as low if not lower HSPF than a 13 SEER one.