I have and use these in vending so I know their strengths and weakness. Knowing all I do I would look at two units. The Traeger COM200 and the Lang 84 Deluxe with warming cabinet. The Traeger goes for $9000 new but can be found for $4500 used or less for the older SMK200 which is the only in an older model but in many ways better than the newer COM model. Both the Traeger models will hold 250 chicken quarters and cook even top to bottom rack. Cost to run the Tragers is about 3 pounds of pellets per hour but with BBQ pellets $10 per 25 pounds at Home Depot, it's good.
FEC100 - Lang 60 - WSM - Traeger