Hard to tell from just a pic but it appears OK. Some staining on top of the piston is normal. The main things I look for are obvious physically broken external parts, bearing condition, excessive or abnormal rust, excessive piston/cylinder scuffing, metal transfer between parts, slop in rod bushings, etc.

Truth is, if it felt good, you probably didn't even have to take it apart. Taking stuff apart is fun though so I probably would have done it too.