You're comparing good systems; however, the Rheem air handler is not variable speed while the others are--so you're not necessarily comparing like systems. The Carrier setup uses 15 kW of auxiliary heat while the others use 10 kW of auxiliary heat. What did you have before? I hope the Carrier contractor intends to provide the extra amperage at the unit if it is needed (60 amps vs. 90 amps needed for 15 kW). Which company impressed you the most? Your Carrier numbers are off a bit (I guess they were hard to read). They should be KFCEH3001F15, FV4BNF002, and 25HCA324 (if Comfort 13).
Here are the efficiency ratings of each setup:
Carrier: 11.7 EER, 14.5 SEER, 8.5 HSPF
American Standard: 11.5 EER, 14.0 SEER, 7.8 HSPF (Note: I only found match-ups with the 4A6H4024B1000A--they may have discontinued/stopped rating the *A1000A.)
Rheem: 12.0 EER, 14.0 SEER, 8.9 HSPF (Note: I would ask for the variable-speed blower--model RHKL-HM2417. This would give 11.6 EER, 14.0 SEER, 9.2 HSPF.)
I'll let others influence the brand selection, but ultimately it should come down to the better contractor and the performance ratings above.