Neither am I an expert but I have the Amerique and I have been using it with near perfect results (according to the wife and friends) in hot summer weather and, more recently, in bone-chilling weather. It makes little difference. The food comes out perfect every time! As for capacity - I'm not into catering but I have easily fed 20-30 people and I've yet to fill the smoker to capacity.
Bottom line - I don't think you can go wrong with the Amerique unless maybe you want to use it for a catering business. Then, you might need something bigger.