First off, pricing here is not allowed. Second, brand is not important. The company that's doing the work is. If you purchased your car like you're purchasing your AC system, here's how it would work. You'd go to the YP and call a few mechanics. The ones you select would advertise various brands of autos. Simple, eh? Not so quick. Now when you've decided which brand you want, you invite the mechanic to your home so you can decide on a model and accessories. The mechanic shows up and has lots and lots of books. Each of the books has all the different parts needed to BUILD a car. That's right, there's no factory building your car, the mechanic has to do it. So now, which is more important? The brand of the car or the mechanic who's going to build it for you? That's what selecting AC equipment is all about. The manufacturer builds the box but a mechanic has to build the system. Get the wrong mechanic and it doesn't matter what the brand on the box is.
If you want the highest efficiency of the United Technology group, you need either the Carrier Infinity Series or the Bryant Evolution Series. Identical equipment in all respects. But I'll bet the mechanics installing them aren't.
If YOU want change, YOU have to first change.
If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!