I've had the Mitsu fe12na for two years now, and am fairly impressed with it. It replaces my old wall heaters quite well. I find it interesting reading some of the reviews complaining about lack of heat at low temps. Mine puts out good heat even down in the low teens. If these reviewers had bothered to read the literature, they would see that there is a significant drop off in efficiency when you drop below say 15 degrees ( and the hyper heat kicks in ). I've had no service issues to date, but I do have a couple of complaints. First, the unit tends to ice up the base drainage tray when the temps are below freezing (and humidity is high), for several days in a row. It doesn't appear to impact the units operation. There is an optional base heater kit that is supposed to eliminate this issue. The other complaint is the fan on the outdoor unit is rather loud at times. I would guess that both of these issues are common to heat pumps to at least some degree. All in all very satisfied.