Great lookin' ribs!
I'd be curious to see what you think about the WSM vs. the MES (maybe after a few times with your WSM)...mostly regarding the taste of the final product.
I was using a Weber kettle for indirect smoking (very limiting in sizes of meat you can use, constantly adding charcoal, tough to regulate temp), until I recently got my WSM.
First two tries were with chicken leg quarters: turned out great! (Look for the Snake Bitten Chicken recipe at this site.) Many thanks to Johnny for WSM tips and mod info to get me up and running! I'll definitely get a welding blanket in the fall.
Next two tries were St. Louis-style ribs...last two weeks. The first was OK, so I had to do some tweaks (mostly to my rub) and try again last weekend. Much better the second time around. Many thanks to JJ for help.
I wanted to try Pork Butt this weekend, but the weatherman isn't helping. Scattered showers are one thing, but thunderstorms? Maybe Sunday will turn out OK.
Good luck with your WSM!