They are the first to make split mobile ACs widely available to the masses. They previously existed but were mainly advertised as camping or boat ACs.
Midea put quite a bit of money into ads, sponsorships, etc but they also simply make a really good product.
I've had a monoblock AC before. Same BTU as the Midea one I have now. It was significantly louder, took way longer to cool the same room, and used more energy.