TurboPrint for the Amiga hasn't been updated in years. But I agree with Mech, printing across my network (you can't use AmiTCP) to my PS printer give the best output and HP inkjets (even new ones) are still supported by the Amiga. Final Writer and PageStream give the best looking documents. It is also easy to change printers with the click of an Icon that runs a short script changing ENV parameters.
As far as the GIMP-print goes, it would likely run under OS4.1 on a NG Amiga; Classics just don't have the chutzpah to get those programs to really run