Except for a pellet smoker and stickburner, I have owned all types of smokers over the last 25 years—kamados, electrics, kettles with charcoal baskets for indirect cooking, and multiple types of each. But bar none, my favorite is my WSM 18" that I purchased in '09. The WSM 18" served me better than all for smoking due to its simplicity (no moving parts), its use of a ubiquitous fuel, and my love for managing a fire.
One of the underappreciated aspects of the WSM is the ability to adjust smoke flavor for different meats and palates. Not all smokers have such flexibility, but the WSMs do, and the 22" doesn't disappoint in that area. Also, with the simplicity of design and some experience, you can learn to manage the fire to hit stable temperatures without the use of a thermoelectric-controlled blower.
When I needed more smoking real estate, although tempted with the new Weber pellet smokers (they look so awesome), I went with the larger version of my G.O.A.T. I ordered the WSM 22" and it hasn't disappointed. Due to my experience on the 18th, it took me only one cook to figure out how to manage the fire and dial in the desired temperature, achieving temperature stability for hours. The extra real estate allowed me to cook two 13 lb spatchcocked turkeys for Thanksgiving on the top grate and catch the drippings in a pan on the bottom grate for delicious gravy with a kiss of smoke.
If, like me, you enjoy fire and smoke management as part of the BBQ process, you won't be disappointed with the WSM.