Ewwwh buoy...
Inexpensive side box smoker.
Not sure what to say there...
No heat sink (water, firebricks, sand, etc) to stabilize the temperate.
Might or might not leak like a sieve.
From what I've seen, usually the fireboxes need modification to get better temp control / more even temps.
Not very efficient from what I've seen - lots more charcoal needed than you would with a WSM or even an ECB to do long cooks, and you have to add every few hours.
All that being said, some people do turn out good Q on small side box smokers. Fairly sure that they are using a better built rig though.
Almost wonder if an ECB with some modifications might be a better cooker than a cheap sidebox. Not sure though.
One great thing about WSMs is the support, it's really unmatched for any other pit out there as far as I can tell. You can have no clue what you are doing, but go to the virtual bullet website, hit the recipes section, and follow the directions word for word and most people will think you're a **** BBQ god, it will come out that good... There is so much more great support and knowledge out there about the WSM, it's unreal. All you have to do is not ****** with things and just follow the directions until you understand what is going on and it will make you a star.