The problem with the "dime store" smokers are design and materials. They use excess fuel because the metal is thin and they "leak" from all openings and not just the chimney. These things even leak from where the firebox is mounted to the cooking chamber. I know this as fact as I have owned several. Once I was enlightened, I saw why these things are so cheap.
Don't know if you have a Bass Pro Shop in your area, but if so and they carry the Horizon (out of Oklahoma), you can check it out and actually see the difference. The one I'm considering, has a $1,600.00 price tag. I'm thinking of setting up a small, roadside business for extra income, once I retire (I wish). It will serve as a home cooker as well.
If you happen to be in the area, Contact Lang BBQ Smokers
, you could check out these guys. They swear by reverse flow.
My large BGE is great. maintains temps perfectly and is extremely fuel efficient, but it just isn't the same as a stick burner and is too small for large cooks. Even the extra large is too small, IMO, for large cooks.