I've had them for years and can't do without it. I've done ribs, prime rib, brisket, turkey, pizza, cornbread, you name it. It's basically a wood-fired oven, so feel free to try anything you would do in an oven. It's not a 550 degree, direct heat grill, so keep your gas grill for steaks, burgers, veggies, etc...
As far as pellets go, I can't tell a whole lot of difference between them except for how they burn. Some burn hotter/faster, while others are cold enough that the fire can go out when on "smoke".
Get one of these!!!! They are a great product, and the company personnel are great people. Known them for a while, both personally and proffesionally, they won't steer you wrong.