Little agreement on this subject. In my write-up on
using a water pan in the WSM, I recommend water for cooking low & slow 225-275*F and no water for high-temp cooks above 275*F. Many people use water in all sorts of smokers, not just the WSM. Despite what people say to the contrary, it not only helps control temp but it also creates a moist cooking environment that aids in smoke ring formation in addition to whatever spritzing you do of the meat. And I've never found water disposal to be a big hassle
if you do it right.
If you don't believe me and my 23 years experience, believe Meathead. I taught him everything he knows. (joke

) From his site:
- Water vapor mixes with combustion gasses to improve the flavor.
- Water vapor condenses on the meat and makes it "sticky" allowing more smoke to adhere. This smoke enhances flavor and sodium nitrite in the smoke creates the smoke ring.
- The humidity keeps the meat surface moist, it evaporates and cools the meat, and that slows cooking . This allows more time for connective tissues and fats to melt.
This is not to say that you cannot make fine barbecue with an empty water pan. Professionals not using water typically spritz during cooking to keep the meat surface moist and cool. Backyarders may skip spritzing and water in the pan and be perfectly satisfied with the results; I don't question their results or satisfaction.