In your opinions, what are your thoughts on (regarding a furnace and central
air conditioner):

Rheem Weather King 80% (Not a variable speed) and a 2.5 ton Rheem AC unit
vs.
Carrier WeatherMaker 58CVA , also 80% (Variable Speed) and 3 ton Carrier
38TKB AC unit

I have to choose between the two for my house and I don't know which to go
with. I don't have any information on either of the two installers that
would help me pick which one was a better installer...both are personally
involved with the installation.

The second quote was more money than first, given it's a variable speed
furnace and a slightly bigger AC.