Kingsford charcoal always provide a consistent burn temperature. This makes it easy to gauge how many briquettes to use. Also, they last longer and provide a great base for flavoring chips. I always recommend Kingsford.
I have used Kingsford charcoal for years. Its the only brand I use to bbq my meats. Like some of the other people I have seen changes in the size of the briquets and sometimes it don't last as long. Other times it works great. I usually buy Kingsford charcoal at either at Lowes or Home Depot around Memorial Day weekend when you can get a twin pack for $10, thats 40 lbs. great price. It usually lasts me until it goes on sale next year at the same time.