Last week I was possessed with a desire to push my printer to its limits and try printing objects at their maximum possible scale within my printer’s bounds. Naturally, Marvin seemed a good place to start. Printed in stainless steel PLA and finished with sandpaper followed by a polishing wheel. In the photos you can see before/after shots, which show the effect of polishing.
Nice clean-up! Sometimes I find using the little metal filer set (you can find them at Home Depot etc.) work wonders in cleaning hard to reach areas for PLA. Maybe try printing something with a pattern or unsmooth texture and see how that resolution is?