I've used Traeger pellets and Gourmet BBQ brand pellets. Both work just fine in the smoker. No real difference between the two. I bought several bags of the Gourmet brand at a sports store that sells grill, called "The Sportsman's Warehouse". I bought them because they had the type of wood I was wanting to try, and cost. They were $13 for a 20 pound bag. The Traeger pellets were $20 for a 20 pound bag.

The type of wood does make a difference. Big difference. I don't know about the blends, but can confirm completely different flavor imparted to the meat with different wood types.

I do not like Maple. It just tastes weird to me.

Mesquite is strong. Tastes great with chicken.

Hickory seems to go with beef. Mesquite does too, but I think I like hickory a bit better. I want to try Pecan next time.

Pecan is good with pork. I've also tried cherry and that was OK. I also tried a 50/50 blend of cherry and pecan, and that was really good.