It can also make ribs taste a little hammy, depending on the ingredients of the rub, and whether it has high nitrite and nitrate concentrations, in amongst the salts, if you are using accent or tenderquick, as a tenderizer, etc?
Mango, 4-6 hours is plenty enough prior rub time. If you rubbed overnight or longer you run the risk of "curing" your ribs if there is any salt content in your rub and getting a hammy taste to the meat as SoEzzy said.
I seem to get a better Bark by putting my rub on just before it goes on the smoker.
I don't want no stinking meat, I just want the Bark!!!!!!!!!!!
The Smoke Never Ends
Smoke On!!!!!!