The Cobb is sui generis in the outdoor cooking market - nothing really compares to it.
Not really a grill, but it can grill. With the skillet, great for pancakes or frying bacon. Others have used it as an oven for bread or pizza.
With liquid (wine) in the moat, it gives a moist convection-like heat that's pretty interesting for chicken and fish.I don't have the wok, but think it would make a good stir fry.
Requires a lot of experimentation. We've had some undercooked, soggy failures, but also some very special meals.
However, you can't really use it as your primary stove and it's pretty pricey.
Still, it's an elegant design, untethers you from propane, and ought to be a cool tool for stir fry.