I have neighbors running it on several vehicles. Only as good as the mounting for the spare tire. Note that there are several types. Those that "hang" over the tire and attaches with straps, to those that use the wheel nuts/studs.
Personally I prefer the bike carrier mounted in the 2" receiver, but not sure how I'd do if the receiver was "far under" the vehicle. Then a tire mounted would probably be OK.
I "never" really trusted the rear mounted racks, but after having hung a rack over the trunk on a Hertz Volvo 850, and then driving some 12 hours to Taos, many times excessive speeds out in west Texas, I actually have some respect even for the cheaper type bike racks. As long as it is properly anchored...
hitch mount or roof mount are by all means the best, most secure, and safest for car and bikes. I worked at a bike shop in my early years and definitely saw the benefits to either a hitch mount or roof (mind that's getting pretty tall on a cruiser)
I tryed every spair tire mount on the market but could not find anything to proporly fit over the spair... ended up going with a hitch mount one, Glad I did now. If you change the size of your tire like I did there is no chance of a rack fitting.
I also use a hitch mounted bike rack that will swing away and still allow you to open the rear door without having to remove the rack from the hitch. I know that Yakima and Thule make very similar bike racks in a lot of different styles. I have the Yakima and it has been bullet-proof.