Are consumer level 3D printers able to print plastic objects of similar quality to ones produced using injection molding? Or is 3D printing useful mostly for the prototyping stage before a design is finalized and a steel mold is produced for injection molding?
They can be, it largely depends on how well calibrated the printer and the print settings are. 3D printing definitely is vastly superior for low quantity production or prototyping (due to the costs of getting molds) but it generally speaking isn't the best for mass manufacturing.