Which way to finish suspension parts - Powder coar or POR-15?

Your MMV, but I have POR-15 coated my floor-boards to prevent rust, and ended up having to redo them after they still rusted . I did all of the prep steps they say to use (marine clean,then metal ready, then POR-15). I have lots of parts coated with POR-15, and am now afraid I am going to have to redo them. I ended up using a product called "Rust Bullet" to coat floorboards. This stuff appears to even make them stronger/stiffer then they were. And you dont have to protect it from UV light with paint like POR-15 requires. Good Stuff.