I do not have a Pellet Pooper, but have seen them in action. They look like they can product some tasty Q and they allow for sleep at the comps. The issue I have seen on the standard Treagers, the metal is fairly thin, so it will be affected by the outside temps. That and the standard temp guage is not that consistant. They do have an electric gauge to fix that issue. You do need electric.
The FEC look more solid, but again I don't own one.
Are you planning to compete or is the a home based purchase.