I tried the Stubbs briquettes about six weeks ago after seeing this thread. When I lit it up in the chimney, it put out a LOT of black, sooty looking fumes and I was kinda scared (okay a lot scared) of wasting a corned beef, a rack of spares, and six hours on the stuff.
I put my faith in the brethren however, and filled up my UDS charcoal ring, made a dimple in the center of it, and dumped in the lit charcoal when the fumes and flames had died down.
Temps stayed at an even 225* for the whole cook without me touching it or making airflow adjustments at all (I always have to keep an eye on things and fiddle around with lump). Also, the fire spread out evenly from the center to the outside of the fire ring. With lump, the burn seems to migrate to the edges of the ring farthest from whatever air intake is open.
I noticed that the fumes from the UDS had a bit of that black sooty thing going on, but it was barely perceptable.
When the cook was done I skeptically tasted the food, and found myself pleasantly surprised and relieved that the taste was great! No off odors or tastes at all, and in fact, this was my first really successful cook not involving chicken. This charcoal drove home the importance of controlling your temperature during long cooks.
I've been using RO lump since then, but I question why. I think in the future I will be switching to the Stubbs briquettes for long cooks involving ribs, butts, and brisket and will reserve lump's higher temperatures and showmanship for chicken.