I have a Large BGE and love it. My buddy has a 18" WSM and loves his.
It depends on what you want to do with your smoker. If you primarily want to smoke and have the need to transport it from time to time, go with the WSM. If it's going to be stationary and you want to smoke, grill, cook pizza, etc, the BGE will do it all.
Now, I do carry mine to BBQ comps but I worry every single time that it will crack. I built a special carrier and lash it down ultra careful. My buddy chucks his WSM in the back of his truck and never gives it a second thought. It's pretty much indestructible compared to the Egg.
Mark - part of Cat Sass BBQ Team. Community Development VP - Secret Squirrel Society (but we don't exist)
Member: Mid Atlantic BBQ Association. Member: KCBS. CBJ # 31818
"Life's too short to drink cheap beer or eat crotchpot BBQ"
NB Bandera - refurbished; Two Big Green Eggs: Poncho - Large, and Lefty - Small; Weber Kettles; 6' fire pit; Super fast Blue Thermapen