The other week I ran out of charcoal so I took myself off to my local Booker to restock before a Q-ing session. To my horror they were out of stock of their Restaurant Grade charcoal and had to buy some ordinary "supermarket" type charcoal.
I cannot stress enough the difference between proper restaurant grade charcoal and the supermarket variety. Restaurant grade charcoal burns much, much longer and imparts a far better flavour whereas the supermarket stuff is nearly burnt out before you're ready to cook, doesn't last for long and has no flavour!!
Nuff said