My 2014 Classic has Hehr Windows. I guess I have never given them much thought, and have not had any trouble with water or air leaks. Given my rig is older, it has the sliding windows, which I really like compared to the pop outs. Sliders really provide much greater air ventilation and I can also slide the screens so my dog can hang his sniffer our the window.
2014 Renegade Classic, 45', Freightliner Cascadia
Cummins ISX15 with 13 speed Eaton auto shift