Been a few years since I worked in the field, but Janitrol was always junk, IMO. Trane bought out GE's residential HVAC line quite a few years ago, and probably improved it in the process, because I never cared for the GE product.
Whirlpool used to make a good unit. York makes a good furnace, but I don't know anything about their condensing (outside) units. Rheem's were always pretty good. If I have to replace my 30 year old Carrier condensing unit, it's probably be with a York. Go for the 75th percentile with regards to energy efficiency.
The main thing when replacing A/C systems is to make certain they are properly sized for the application, and the climate. IMO, a lot of units installed in newer homes are undersized...there's a fine balance there. Most of the work an A/C does is removing moisture, so it must run long enough to do a good job of that, then it can cool the air as well. If it runs for too short a period, it won't remove the moisture (humidity) and in the long run will use more energy from short cycling. Another tip is to have the condensing unit on the East or North side of the home, if possible, or plant some shade trees/bushes to shade the condensing coils from direct sunlight, particularly the afternoon sun, but keep 18-36" of clearance all around the unit, and make sure the fan discharge is not blocked in any way. The outside condensing coils should be cleaned each spring to remove debris and dust/dirt so that heat transfer can take place more efficiently. Inside filters should be checked/changed as needed...a clogged air filter will cause the refrigerant to transfer less heat, which can result in compressor valve damage.
Good initial installation and proper charging of split systems is the key to long life for the compressor...it depends on the refrigerant for cooling it's windings down while running, but it must be in vapor form, and a proper charge ensures this. The suction (larger of the two) lines going into the unit should be cool to the touch, and insulated, and will probably sweat a bit in the hottest/most humid times of the year. The smaller line should be warm to the touch and uninsulated.
Better units have a time delay start so that when the power blinks, or somebody turns the unit back on right after it's turned off, the system will have time to equalize before the compressor tries to start against a load. The discharge (high) side of the compressor is typically running 210-280 PSI and the low side 65-75 PSI in stable running conditions, so it's important for the unit to equalize before another start is attempted...takes a couple of minutes for that to happen, generally (heat pumps are exceptions to this).
Just a few tips to increase the longevity of your system...