Pros: Simple to use, set it and forget it. No need to babysit it for hours on end, just make sure the hopper is full.
Cons: Some people say the food isn't 'smokey' enough. These are usually guys that have/had stick burners. Although if you want more 'smoke' flavour a lot of people toss a smoke tube in and that usually solves the problem. Mine wasn't cheap however, probably around $1000CAD after it was all said and done. But like my BBQs, I do my research and buy a decent one. I've still got a Vermont Castings BBQ I bought in '06, still going strong.