i did look at them but i couldnt see how they would work for an overnight stop where you're not unhooking the van from the car.
@Brougham - You are correct - I doubt you could drop it with both the bikes on and the car attached if it wee on the draw bar. You can mount the ISI to a rear receiver (as per what you have done) and it would drop fine.
Personally I have no issue removing the bikes as it is seriously quick and almost effortless - you wouldn't believe it until you saw it. The only effort is lifting the bike and you can even reduce that by removing the uprights - 1 simple thumb screw (in fact it probably doesn't take any longer - if you remove the upright than the hook that holds the bike doesn't need to be removed).
I have never stayed without unhitching the car anyway.
So I guess it comes down to personal preference, budget and needs as to which way to go.
I would trust the ISI on the draw bar over any bike carrier mounted on the rear every day of the week, but draw backs are added towball weight of the carrier/bikes and cost.