I was advised by my aircon service guy to take up Panasonic because unlike other brands they have 2 compressors. Compressors are like the heart of the aircon, if it dies on you, you have to replace the whole outdoor unit. Therefore, with Panasonic, you have two hearts. If one breaks down, there's another back up hence longer lifespan.
But of course, I can be wrong. Maybe the service guy feels that it's easier to clean Panasonic ones. So far, fm my experience, National @ mom's place is lousy (always need servicing, change this and that) Sharp @ work place is super duper noisy but live up to the warranty date and Mitsubishi electric Starmex @ current rented place is cool & noisy at times (maybe too soon to tell, a few mths shy from 3 years)