We print with PEEK daily. We get good filament from Solvay, and we print with the head at 405C and the bed at 150C on a powder-coated PEI build surface.

For anything larger than 15mm in any direction, we print a dam around the entire model to keep the local air temperature higher than the ~55C we can manage in the chamber. For anything larger than an adult fist, you're going to want something with a chamber at 100C or more (which we don't offer... yet).

Last tip: you want to basically anneal the PEEK part after printing and any cleanup; by heating and then slowly letting the temperature drop, you cause longer crystals to form, increasing strength and making the finish more uniform in color.