I've got experience with Backwoods & Stumps, plus am familiar with the Superior.
My preference is for the gravity/continuous feed style. Early Stumps were plagued with charcoal delivery problems and distinct temperature variations in specific areas, top to bottom and side to side. The more recent design changes have improved the charcoal feeding, air flow and heat distribution. Both gravity fed brands are extremely efficient with or without the use of temperature controllers (guru or stoker), primarily because they flow very low volume of air, use precise valves to regulate airflow/temperature and they don't require a water pan to help with heat distrubution and temperature control. Alot of energy from the fire is used to heat up and maintain temperature in the water pan, which is continuously changing through evaporation and refilling. The builders of the cf/gf smokers advertise 15-20+ hour continuous burns without refueling.
The Backwoods and Spicewine will have many experienced users that will brag of similar or better operation. Those brands are designed as water smokers, they can operate without water, but will requre more practice and baby sitting to maintain constant temperature.
All the verticle cabinet smokers are well built and fully insulated making them suitable for all seasons and very versatile in numerous cooking methods. All have unique differences, check the web sites and brand specific forums for all the details.
[FONT=Tahoma]Big Tom's BBQ Shop [/FONT]
[FONT=Tahoma]Pigs-R-Us Cooking Team[/FONT]
[FONT=Tahoma]Owensboro, KY / Corinth, MS[/FONT]