I wanted the charcoal/wood profile so that ruled out electric and gas. I want quality and efficiency so that ruled out non-insulated and cheap. Spent some time reading people's reviews of different cabinets. I looked at the websites and asked some questions of the builders. Some of the builders didn't make a model in the size I wanted or the cost was very high for that size. The gravity feed units require you to add the wood separately and a few people said the flavor profile was not as good. In some of the units you must use water to cook. Having spent 40 years as a sheet metal guy I looked closely as the gauges of the materials, the welding and overall construction.
After looking a quite a few builders I was able to narrow it down to Pitmaker, TK Smokers and Lone Star Grillz, with Pitmaker running a close third. Both Pitmaker and LSG offered carts with shelves. Tk did not but it's construction was up there with LSG.
In the end I went with LSG because the fit and finish is exceptional and the fact that I had not heard a bad review of their offset smokers. I will be able to run up to 50/50 charcoal and wood. The grates are not expanded metal but nickel plated bars. The water pan, though built in, is 1/4" steel. Plus I heard their customer service was outstanding. They were very response to my questions, answering them completely with reasons why they build it the way they do.