I've got too many racks. For our SUV, we have a hitch mounted beefy 2" reciever Hollywood rack.. we could take it 4 wheeling and it would still be stable. Note- on hitch racks you really need to stabilize the wheels so that the bikes don't swing, this rack has that built in.
I have 14 year old yakima trays on top of my subaru, not recommended for taller vehicles.
I have two strap on racks, the $12 gargae sale special is incredibly stable.
You can get roof rack "bras" to protect the paint but I don't worry about it with mountain bikes.
Irulan
2015 Liv Intrigue 2
Pro Mongoose Titanium Singlespeed
2012 Trek Madone 4.6 Compact SRAM