Not true sir, unless it was meant as sarcasm.
I live in Phase 5 DHA, about 6 mins drive from Seaview and 15 mins from Korangi. We have 9 Split Airconditioners in our house and one window unit. We have used Haier, Samsung and LG. All failed within 2-3 years. Now we replace them with Mitsubishi units. The earliest Mitsubishi units have lasted us for 6 years now. Even this year, an old Sabro unit failed (rusted out, Sabro being a shyt company, yet their AC lasted 10 years!) and instead of wasting money on inverter maar ka ACs, we paid for a Mitsubishi non-inverter Unit.
Our old General Window AC is still going strong. Age= 20 years.
If you want to protect the outdoor units from rusting out, please don't mount them on top of the roof of the house. The dusty wind combined with moist sea air, means, the dust will first rip off the paint on the unit and then the moisture will proceed to eat out with rust. Just mount them on the wall. So if you have a house next to yours, then the side mounted units will at least be shielded from direct winds.
Another thing i have noticed is that Mitsubishi units rarely need refrigerant recharge every year. Most last 4 years easily.