I've owned my 18.5" WSM for a few months now.  I have cooked a couple large pork butts, a few racks of ribs and a Tri-tip roast.  I am learning as I go and have been extremely pleased.  My first smoker was the gift of a gas smoker.  That got me hooked but temperature fluctuation was a nightmare.  I have been impressed with how easily this maintains a temp.  I really prefer charcoal to other fuels I have experienced.  Clean up after each cook is super simple.  It fits like a glove on my patio with my three other Webers.