Another option we had installed on our 2014 2552 is the Coleman Mach 8 15,500 btu A/C unit with heat strip. This was not an additional unit, but rather a substitute for the standard A/C. It is also a standard A/C unit, not the heat pump version.
Here is the odd (to me at least) thing about this unit. Switching the thermostat to electric heat may or may not also turn on the furnace. It depends on the differential between current room temperature and where you set the temperature you want. If the differential is more than 5 degrees, the furnace lights and runs along with the heat strip until a 5 degree differential or less is reached. It makes sense to operate like this and it certainly would not be everyone's ideal way of operating, but you can just run the heat strip if you remember not to crank up the heat beyond 5 degrees above current room temperature. I'm going to live with this way of doing business for a while and see if it becomes a hassle or great feature. One could always install a second thermostat or just a switch for the heat strip.
The only other thing I can report on right now is the fan noise. On high, it is loud. On low it is quite quiet....very easy to carry on normal conversations, not distracting at all. I guess this is all subjective, and again I don't have the stock unit to compare it to, so if you're interested in hearing it for yourself, look us up! - Mike
Mine is the HP model and the noise levels are as Mike describes. I was disappointed when I found that the heat cycle only operated on High. I am going to contact Coleman and see if the fan speed can be changed at the unit. I ordered mine with a separate thermostat for the gas furnace. The HP is not efficient below 45 degrees and the gas furnace on it's lowest setting works for those few days that it gets below freezing in the Sunny South.