I always preferred Qt over GTK just from quality POV, if you are not a C++ hater then Qt is perfect for cross platform professional looking apps.

And about this designers forcing their shit on users, I hit lately a issue with GTK apps where the windows of the app and popups are hard coded and you can't resize them. Because of my bad eyes I use a giant font size and this apps are unusable (I need to research if is possible to trick this windows at runtiem that they are allowed to resize)