What makes Mitsubishi so good and others not as much
This is from my experience so not sure how well it would translate for others.
1. Service Quality in my area is top notch, I know this will wildly differ for each person but this is my one of my biggest pros for Mitsu, We have had our Daikin/Samsungs serviced quite a lot and there were always some little issues that used to pop up and for our Daikin, we needed to get its external fan assembly fixed once and after that cooling was never upto par than what we had before.
2. Heating, we have had a couple of Cool/Heat ACs and Mitsu definitely has the better heating, the room heats up quite fast and the air does not smell acrid at all (the biggest pro for me), my parents used it all winter long and there were never any issues with it, We also have a Daikin in our home and compared to Mitsu, the heating falls way short of the goal. you really need to increase temps for Daikin to heat the room properly whereas with Mitsu, a cool 26-27C sufficed to make the room hotter.
3. Cooling, both Daikin and Mitsu are on par for us but Daikin's cooling really went down the drain after the aforementioned service, and Mitsu beats it hands down now. We bought both models in roughly equal time frames (I think we got the Mitsu after 4 months) so it should be a fair comparison in regards for longetivity.
4. Noise, Mitsu is quiet af in normal usage, We have had a couple of Hitachi/Samsungs (non-heating, vanilla ones) before and the noise levels used to be almost on par with Window units specially if it was really hot outside, in comparison both Daikin and Mitsu have lower noise levels.
These are pretty much it for me, We have used other brands before but Daikin/Mitsu have been better for us but comparatively they are also really expensive compared to a decent Samsung/Hitachi etc
P.S. It's been a while since we bought any new ACs except for a Mitsu which we got for our cousin's family and they have been just as satisfied with it as we, so take my review with a grain of salt