I have a gold and a silver, one with one vent and the other with three vents. I would agree that the gold's side vents could make it a challenge to keep the coals hot enough for grilling, which seems to be the biggest issue with the gold. But low temps are very easy with the side vents (provided your vents are flush with the bowl
). And as Hogsy said, 18 hrs isn't impossible.
If you're looking for the versatility of grilling and smoking, then I would go with the silver. Like everyone else, I added a short can wide enough to cover the bottom vent to keep the ash out of the vent. Probably went overboard on it, but here it is...
I haven't put the pot on the three vented silver yet, but my thought is I might have to treat it like a wsm and poke at the vent holes every now and then with a thick wire.