I'm a hvac mechanic and I would recommend Bryant or carrier,Lennox is ok but they seem to leak a lot more than the rest in the a coil in the furnace, I'd also recommend going with an actual heating and cooling company not big box stores better service and support local, also make sure who ever puts it in actually knows how to diagnose and fix if something goes wrong way to many guys out there that don't know what they are doing and screw things up in a hurry
Well said, definitely make sure they are an journeyman refrigeration and air conditioning mechanic, not just a tin basher or plumber. Nothing against said trades, Some of them can certainly install AC but as noted above troubleshooting and diagnosing any issues would be a different story.