I was never happy because they were hard to regulate the heat and needed numerous modifications to work in a semi-acceptable way.
Then, I started doing some research and found the gold standard... Stumps Smokers.
I started with their smallest vertical gravity fed smoker, the Stumps Baby:
Produced in the good old USA by the good folks at Stumps Smokers in Centerville, GA. It is an amazing piece of equipment.
It came professionally packaged: