[LEAKYSEALS951]

top mounted racks and rear hitch racks both have their strengths. You just need to decide which works better in your situation.
Top mount- out of the way, don't need to worry about getting rear ended (bikewise)
cons- you have to reach up to mount them, wind noise, reduced gas mileage, need to remember not to drive under low awnings, hassle of removing front tire on some models. The panoramic sunroof thing scares me, particularly on front fork mounted models, where with the wheel off, the fork tabs could crack the glass, but in experience, I've had pedals hit the roof too if the bike falls over.

Rear hitch- easy to get too, easier on gas mileage. Invisible to gas mileage on rear of my wagon.
cons- easier to get bike rear ended/ not good for vintage irreplaceable bike. Also, rear hitch can hinder access to rear gate on station wagons/suvs.

I've used both, a lot, and am currently in a rear hitch phase for convenience, flexibility between bikes, and mpg reasons on my commuter car.