I have a fatboy and love it. I use a guru with it and have no trouble getting burn times in excess of 12 hours. I've had to re-fuel during a cook only once and that was because I didn't have enough charcol to start with.
Klose 24x50 BYC
[COLOR=blue]Rock Chalk Jayhawk Blue[/COLOR][COLOR=black] Thermapen[/COLOR]
Weber Gasser (out of gas)