Mo@#$%^&* ..need A/C and Furnace replaced

We literally just replaced our HVAC setup from 1981 a couple of weeks ago. Just like searching for car parts online, I found a great deal on a Goodman 3 1/2T 16 SEER unit for well under $5K with free delivery. It's made in the USA (unlike most others today) and has a wonderful reputation. Here's a link to get you going Goodman GSX140361 ARUF37C14 3 Ton 14 SEER Air Conditioner Split System R410A Refrigerant. Tommy, the guy who installed and hooked up everything, said HE couldn't even get them that cheap. It was such a good deal Billy even kicked down for the whole-house HEPA filtration system (he has allergy issues).
I put a few days into reading those review websites. I knew going in that very few consumers will take the time to write a positive/praise review. Every brand has its share of negative reviews, some more than others. So there isn't a brand with "wonderful reputation". There isn't much difference in any of them. Same compressors, fan motors, etc,, in most of them. In fact the most notable difference is design of grille over condenser fan, how much noise they make. Carrier is exactly the same units wearing at least 3 different badges and grilles today.
A independent research study couple years ago found that more than 90 percent of the service calls on units 5 years old or less were directly related to the quality of the install. One brand might be more rigid at bulkhead/refrigerant line attach points but.. if the installer would properly support the line set at evaporator that wouldn't matter. At the same time, some settling of a nearly 300 lb condenser unit should be expected and allowed for, especially at new construction.