In reply to Rob Exile Ward:
I've got one of them... I've had three bikes on it but i can't say as i was particularly happy about it; parking sensors don't work anymore, visibility is buggered due to bikes covering the rear window and poking out the sides so wing mirrors aren't great, fuel economy goes through the roof and i'm always paranoid about straps working loose and people pinching bikes. In addition, even though it's mounted high, it still obscures licence plates so you're supposed to have an extra board with lights and plates.
I chuck bikes in the boot with wheels off and if there's more than one, i pad out the metal-on-metal contact with karrimats. there's enough space in my octavia saloon for two bikes, plus two riders and a dog...