JeffW - or anybody else that wants to chime in - have you ever had any problems with your strap comming off of the receiver mounted hook?

I am trying to figure out why I should or shouldn't spend $40-50 on a receiver mounted shackle when 4 wheel parts is selling a receiver mounted hook, strap, regular shackle and bag for $59.

So is there a huge advantage to using a shackle instead of a hook? It seems to me that the majority of the time, the answer would be no.

Opinions?