If you’re buying pellets in 40-lb bags, singly or by the ton, then you may actually have a choice in what pellets you buy. The bagged pellets for sale in your area can come from any number of plant locations in North America. They all say “premium” but you may find you like some brands better than others.
Pellets generally are produced in one of three ways: 100% softwood, 100% hardwood, or a blend. Unlike with non-pelletized wood, the softwood pellets have a slightly higher energy content. This is because once the wood has been pressed into pellets, the result is a similar density for all (about 40 lbs per cubic foot). Pound for pound, the softwood pellets have a slightly higher energy content. The softwood pellets also tend to ignite a little easier.
One other thing, though this is something that you probably don’t need to worry about: your pellets must be made of wood only. If the bag says wood pellets, there’s little chance there’s anything in there but wood. Pellets made from anything else, like grass, will most likely contain higher mineral content with a lower melting point, leading to more ash and clinkers.
High moisture content is something alse to avoid. It raises the risk of creosote build-up. If your friend is looking to sell you some wood pellets and they look like they’re cracking, clumping, or falling apart, chances are they got wet. Even if they’re dry now, you should avoid them.
Ultimately, if you have good experience with one brand of pellet and the price is competitive, there isn’t much incentive to change.