I have 6 grills and smokers of various sorts. In Asia: a gas grill bought at Costco gets the most use, followed by the smoker (without a separate firebox), and of course a weber. In California, we have a propane grill with cast iron grates that I really like, a smoker with the firebox on the side, and an upright smoker.
Propane is used more times than charcoal, but the overall "amount of time" that charcoal is used is greater.
My favorite: smoked rib roast. Rub with seasoned salt, garlic power and black pepper (or Cholula chili and garlic power plus some kind of salt). Light the charcoal in either the firebox or on one end of the smoker, and soak some mesquite chunks. When the charcoal is ready, put the roast in the smoker on the opposite end from the charcoal and place a couple of chunks of mesquite on the coals. Try to keep the heat between 200-225F by adjusting the air. Prepare and add hot coals as necessary, and add a couple of mesquite chunks when the smoke stops pouring out (30-45 min) for the first 3 or so hours.
For a very tender melt in your mouth roast, cook at 200-225 for about 8 hours. For the folks out there who prefer that the roast slices easily or prefer rare meat, 3-5 hous will do, depending on how hot your smoker is. Hickory, cherry, apple, or almond chuncks also work well. I have heard old grape vine wood is fantastic, but haven't tried it. Never use pine or that type of evergreen...you'll have to throw out the roast...and the smoker!
Enjoy!
R