i'd go longhorn.
Clams, please elaborate. Tia.
One thing I have been reading about the WSM is that ppl close the vents after cooking and can put the firebout thus saving the fuel for another smoking session. Also, there is a firing methid called the minion method that sounds like it makes it so that you don't have to reload it for smokes up to like 12-14 hrs long as long as you get control of the vents well.
As for the longhorn most every forum I have read talks about 4 or 5 modifications that they say are needed to get a consistent temp across the grill(seals, door latches, additional vent, heat damper at fire box, and some ppl even lower the stack.
From reading a bunch on it the last two days, it sounds like both are very good, but that the longhorn uses a bunch more fuel and takes a lot more initial work to get to the same level of control that you get from the WSM out of the box.
I don't think I can go wrong with either, but am leaning to WSM right now.