The Weber Smokey Mountain (WSM) Vertical Water Cooker is a great smoker. It's low cost and quality features make it a favorite among the backyard smoker barbecue crowd. The features include a ceramic coated steel body and nickel plated grills. It has two cooking levels that allow you to have two barbecue dishes cooking at the same time.
The WSM is unique in that it comes with a ceramic/metal pan for holding water that provides moisture to the food while cooking. It will hold a load of charcoal that lasts a solid twelve hours with the proper venting. I use my WSM for pork butts and briskets all the time because it is convenient and easy to use. It beats my bigger offset smoker for the smaller “Q” smoked meat projects.
Weber just released a new model (22 inches) that is larger than the current model (18 inches). This makes the WSM very similar in cooking surface to the average Ugly Drum Smoker (UDS).
I have friends who are crazy about their UDS cookers. Most UDS cookers start life as a 55 gallon drum that has been cleaned and burned out inside to eliminate any contaminating substances. Holes, for air flow, and grates, for food, are added to make it functional. A charcoal box is also added to be the heat source. Just like the WSM, cooking on a UDS is directly over the charcoals.
The UDS cooking surface is also larger than the traditional WSM. A UDS, as a rule, does not include a pan or bowl for water.
A UDS is the really “low cost” alternative for real smoked barbecue cooking because most projects start by finding a throw away 55 gallon drum. You just have to account for the time you spend making it (which can be substantial) for a real cost comparison. There are several resources on the net to describe how to make a UDS.
For those that don't have the time (or the inclination) to make their own UDS there are ready made ones on the market. The cost is still relatively low and comparable to the WSM.
The unique thing about the UDS is that the drippings from cooking fall directly on the hot coals. This produces a distinctive taste for the meat that many aficionados attest is the closest thing to early times barbecue cooking.
Now, to the question of which one cooks the better barbecue…. If you like the taste of the meat drippings on the coals then the UDS wins, however, you can achieve the same effect in the WSM by removing the water pan.
If you don't like the taste of the drippings on the coals but like the simplicity and cost of the UDS just add a pan and grate below the top grate on the UDS to catch the drippings before they hit the hot coals.
They are both super, low cost, alternatives for cooking great smoked barbecue. It's just personal preference.