I'll throw my $.02 in here.  The rear hitch racks that hold 4 bikes can be a pain when you have different sized bikes (kids and adults) and/or different style frames (sloping vs straight top tube)
It's a puzzled to get our four bikes on it.  Plenty of scratches on the bikes, despite adding pipe insulation over frames here and there.  For 3 bikes, the 4 bike carrier is great!  If it is a day trip, I but one bike in the (honda) van and hang the other 3.  
The kayak trailer I'm building will have a bike option on it as well.
John