I used galvanized 4" snap together duct pipe for my system because it was cheaper and easier to ground. Whether anyone has had a fire because of static charges in the airstream I don't know but all the ads for ducting include grounding options and I don't want a fire so I didn't take a chance on it. The galvanized ducting fits together with the pvc fittings and blast gates, at least for 4" sizes. Some of my tools are connected with hose and it fits on the ducting too.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.