^^^^^^^
G$'s answer can't be any more accurate. Its dead on.
its a matter of controlling smoke density on a stickburner. With my stickburners I can go from a heavier white smoke to sweet clear blue in under a minute. When cooking for my wife and daughter, you will never see any smoke coming out of the chimney, just clear heat.... and the food has a wood roasted flavor, with little smoke. When cooking for myself, or a backyard party, I will go a little blue coming out and layer on some heavier smoke. Its all in fire control.
This can be done with the vertical charcoal pits, but i have found that this can have an effect on temperature and you will have to factor in some recovery time when laying on layers of smoke in between heat cycles. But sweet blue, or clear heat, or smokey white can be attained with any of the pits once you master its fire control and the pits draft characteristics.
IMO, when comparing the vertical cabinets to the stickburners, the SB will give the cleanest smoke and better depth of flavor.
(Not taking away from the uprights, I have those also. I use both pits based on what I feel like doing that day)
on edit.. Disclaimer..... By verticals, i was thinking WSMs and insulated cabinet smokers. I forgot u were asking about the UDS.. not sure if this holds true for those... i never cooked on one..
Yet..