I use a Küat NV. It's a bit pricy, but it's really nice. It's hitch-mounted but the installation doesn't require tools and takes about 30 seconds. The rack doesn't touch the frame at any point. It seems to make people nervous when they put a bike with fenders on the rack, but I do that all the time and haven't had any problems. It also has a built-in cable lock (which I trust to keep a bike secure as I go through a drive-thru if I'm in the car -- I carry a chain if I want more security) and a built-in work stand (removed in the picture below). There's also an add-on you can get if you need to carry four bikes.