I had a three bike Saris Bones and loved it. My only issue was that the rubber feet would scratch the car but I found out that putting a soft cloth under them took care of that. Oh and if you plan on putting it on and taking it off often the straps are kind of a pain to keep adjusting but as it turns out they have a new Bones coming out soon that apparently eliminates the straps. Check it out here.
http://www.saris.com/p-258-bones-rs.aspx