I still hear folk complaining about QHY's flaky drivers, so that'd swing it for me personally. Doesn't really matter how the camera looks and feels if it lets you down in the field...
The gain settings with the QHY interface are also quite convoluted. ZWO took a straightforward approach. Each to their own.
It's quite common to see this kind of snobbery towards ZWO, but the reality is in practice there's no difference. At comparable price, it's a question of flipping a coin and taking your chances