Just like your kitchen oven, a pellet grill must keep a consistent temperature in order to produce great food. To get tender brisket, the temperature needs to stay as close as possible to 250°F for the entire 12-plus hours its cooking. A pellet grill’s ability to do that is largely determined by its control board, which is essentially the brains of the pellet grill. There are different types of controllers, and their precision and consistency varies. Most can hold a consistent temperature in ideal conditions, but not all controllers can maintain a tight temperature in the cold, wind, and rain.
Another option is to put a griddle (or GrillGrates) on the pellet smoker when it's cranked to high heat, get it blistering-hot, add just a little oil to prevent sticking, and sear by conduction on the metal. It should take only two to three minutes per side. This is a good technique for reverse-seared meats: You start them indirect, low and slow on the cooking grate, with a little smoke, and then sear the surface with direct contact to the hot metal griddle to create a delicious brown crust. It's not as good as searing directly over hot coals or gas, but it's a good compromise.
Although these are marketed as grills, they do much more, including baking or roasting. Because they heat by convection, you might not get the grill marks that a gas or charcoal grill will give you, but you also won’t have the flame-up problems. While many pellet grills offer high cooking temperatures, the maximum depends on ambient temperature and wind. Many users wrap their grills in special insulating covers to help maintain heat, reduce fuel use, and reach the higher temperatures they desire.