You and the previous raise a good question for me. I'm sure each has it's place but when is stick better than mig and vice versa?
There are a couple times I use stick over a MIG.
Unless you are using one of the cheap buzz box stick welders, they will usually crank out a lot more heat than a wire welder. Not only does that give you the heat you need on heavy metal but allows you to use thicker, heavier electrodes.
The electrode selection is another advantage. Instead of the pain of changing out wire, you can grab a heavier (or lighter) electrode, or more appropriate one to the metal you are welding. Do a little googling and you will find recommendations for clean metal, rusty metal, iron, high nickel, stainless, etc.
Also, on my farm equipment, not only is it usually heavier metal but it is usually outside. Outside means wind which can disperse your shielding gas resulting in poor welds. If I am welding thin metal and want to use MIG and can't get it indoors, I will try and shield my work area from the wind, BUT still keep good ventilation...sometimes at odds with itself. Ultimately I can switch from solid wire to rosin core and skip the gas but that is a pain.