I was thinking about going this route, but I was concerned that with the additional leverage of the rack itself, a bike (or pair of bikes) might do some sheet metal bending where the hitch mounts to the body. Particularly on rougher terrain where some bouncing about may occur. I was also concerned that I might have insufficient road clearance (for the bike's wheels) because I have rather large frame bikes.
Since I have a wagon, I went with a roof rack -- which of course, has its own concerns. Sigh ... And I even had a nice receiver type rack left over from a prior vehicle. Well, now I've got one of each.
If I had been planning to actually do some towing, I probably would have at least tried out the receiver hitch, but I wasn't planning on towing.
I have the Da-Lan hitch. It works great. I regularly put 1 or 2 mtn bikes on my car at least 3x a week.
I have also towed 1000# trailer for 2700 miles with no problem. The sheet metal bending is definately a non-issue.
I have a Thule 2 bike rack with mine and the bikes sit up pretty high, you definately won't scrape the bikes. I have scraped the bottom of the rack maybe 2-3x but no big deal.
This is a pretty good setup, you can open the trunk with the bikes attached too so that's pretty cool. The Thule rack isn't really the greatest rack though, I had to modify it a bit after the bike mounts broke. They were just cheap. Also be aware that you will lose a few MPG with this attached to your car. I get about 26-27 on the highway with one bike. Versus 30+ on the way with no bikes.