If you're serious about the competitions, I think it is definitely worth the upgrade, just for the extra space. If you're like me, and just grill for friends and family, not so much, but you specially mentioned it being easier to use in the cook-offs, which I'm assuming are pretty much the exact same thing as what I call competitions.
I don't have a 22" myself, but the only real issues I've heard are what was mentioned above: the access door needing bending to fit right, and the charcoal grate sitting near/on the vent tabs. Someone that has a 22" can chime in on these issues.
Bottom line: if you plan to use it for cook-offs, I definitely think the upgrade is worth it. Besides, then you'd have two WSMs, and more is better, right?