I had a Lennox SL280V and 14ACX installed today. Price was $2500 less than one of my other quotes.
The sales guy (John) did a load-calculation on my house, which none of my other quotes did. He was easy to deal with, no high-pressure, used-car salesmen taint to him.
The installers arrived today, and had it all installed in a few hours. The install looks (to my untrained eye) to be very well done. Everything looks good/clean/neat. It appears that no corners were cut in the install..I expect this system will last a long time.