I have the XL BGE, and I have looked at the Big Joe. Looks to me like KJ did a great job improving upon the BGE. I like a lot of features of the KJ over mine, and would probably trade even up if anyone offered. BGE has a cult like following and you can go to events to learn etc. I think either is a good choice, I like the stainless, and the bigger ring on the KJ. I think their gasket is a quarter inch wider than the one on the BGE.
(4) 18.5" WSMs
Weber OTG 26.75"
Worlds Fastest "Green" Thermapen
"Not a competition cook, just a guy who loves eating and cooking Q."