Agree. Aside from ease of access, having bikes on the roof is a huge aerodynamic drag. I see a noticeable drop in highway fuel economy when carrying bikes up there, plus it's noisy. They also seem more subjected to the elements, bugs, road grime, etc plus the aforementioned fear of sheering them off while driving under an overhang or into a garage.

I would say that a hitch mounted rack would be my #1 choice for carrying bikes (assuming they don't fit inside the vehicle). They can affect back-up-camera/parking sensor aids so be careful when reversing, but otherwise this setup is much easier to use and doesn't affect fuel economy as much. Unfortunately, on some cars (mainly coupes and sports sedans... where bike racks are even more critical) installing a hitch might not be possible, or might require a custom job that modifies the rear bumper and/or exhaust. If I had a taller vehicle like an SUV or van, I would 100% go with a hitch mounted rack.