My 2014 Mazda 3 has the flip up HUD so I'm used to having it and appreciate it on that car that it projects directly to the windshield. Only issue I had was when wearing polarized sunglasses. I have rx Oakley sunglasses and it makes the HUD really dim. Ever since I tinted the windshield I never had any issues with it since. I love the HUD
I have the same issue as well with my polarized Oaks. I have to crank up the brightness on those days.