Try smoking a boston butt for 18 hours using up only 3-4 lbs of lump charcoal and never opening the lid till it's done.

Try cooking a whole chicken at 400' by simply closing the lid, regulating temp by the damper, and opening it 1 hour later to have a perfectly golden brown (not burned) whole chicken (spatch-cock) that's completely done and dripping with juices and never opening lid till you pull it off.

Try smoking a 10 lb brisket for 15 hours at 220 with on 3lbs of lump, with out any kind of water pan or adding more fuel and have it come out moist and juicy on a metal grill/smoker.

Try baking bread, pizza or potatoes on metal grill smoker.

Lastly, try grilling a steak at 750 or 800' when a small child comes by and puts her hand on the outside of the grill. Outside of the Grill dome (or Egg, or Primo) will be hot but not blisteringly so. (Huge safety difference)

Instead of the heat radiating out of the cooker, it radiates back in towards the food. It makes for more even cooking, more efficient fuel usage and more consistent results in evenly cooked food without the hot and cold spots associated with gas grills.
I was looking for "the best" gas grill (had no desire for a "charcoal" grill) when building my new house about 4 years ago. During my search I kept coming across "the big green egg". I had never read so many customer reviews that raived about their investment, some posted several years after they purchased. Then I ran into a few people who owned them. My aquaintences' comments went something like this. "They make for the best steak you've ever had" etc., etc.
Then upon researching ceramics I settled on a Grill Dome. But I only live an 90 miles from Atlanta where they are distributed from so I didn't have to have it shipped. It saved me about $150 over a large Egg. But whether you want an Egg, Primo or Grill Dome (Ceramic Grill Smokers), any of these will make for the most flexible, consistent, and easy to use grill-smoker-oven, you could ever buy. It's one investment you'll never regret and you'll only miss the money till you've cooked your first meal on the Ceramic. Check out their websites and forums. The Big Green Egg has the best forum. Hang out there a while and ask them your questions or concerns then make your decision as you see fit. Just my two cents

PS, I'm originally from St. Louis, "Go Cards!" "Where'd you go to High School?"