We have tried several bike racks over the years with limited success.  A hitch mounted one and another that attached over the rear spare tire on a SUV.  Both of these racks were made by "Bell" and were junk.  This 4 bike "Allen" rack is sturdy and well built.  It sets up quickly and I like the two extra side-straps instead of 4 mounts (two top and two bottom) that most trunk mount racks have.  On the down side, its hard to get 4 bikes onto the rack but we have had success with 3 adult sized bicycles.  Maybe with a mix of adult and kids bikes would fit four.  We have used the rack for the past 3 weeks everyday after work.  In fact it has not come off the car nor have the bikes except when we are riding them.  The rack stays in place with bumps on the road and taking corners and turns.  Nice piece of mind when you are hauling costly bicycles.  The rubber saddles strap the bikes securely and don't scratch the bike frames.  We are very happy with this quality bicycle rack.