I think ratherbhuntin covered it pretty well. Over the years I've owned a lot of different smokers including a weber WSM which is without a doubt one of the best metal "bullet type" smoker/grilles...my Big Green Eggs are without a doubt better and more versatile. The WSM was overall a good little smoker, on perfect days I was able to get some pretty impressive cook times out of a single load but try to maintain temp on a windy and/or cold day and things get a lot more difficult. The ceramics don't care if it's June in Ga or a windy winter day in Alaska. Another thing most charcoal and gas grille users don't realize is you can have your ceramic cooker up to temp and cooking just about as fast as you can have your gas grille up to temp. Also with the ceramics when you are finished cooking you shut it down and when you want to cook again you simply stir the left-over lump from the previous cook and relight it.
You can make good food on any of them, IMO the ceramics make it easier and are much more consistent.
