I am sorry to hear that you have a bad experience with your carrier equipment. Let me assure you that Carrier is top of the line equipment. Unfortunatly, every mfg has their percentage of "less than desirable" pieces leave the factory. It seems that you have one of these.
The 90% equipment have been produced since the mid eighties, and by the early nineties most of the bugs were worked out.
My opinion of the the new equipment is that they are far superior to the old, but for life expectancy I would think that they will not last as long as the older stuff. The circuit boards, sensors, ignitors that did not exist in the older stuff won't last 30 to 40 years.