some bias out there for the G version,, I personally like the 1.4D which I own (own both 1.8, and 1.4 D versions). the build quality is solid and more compact then the G version.
I have a variety of 50 mm from 1.2, 1.4, 1.8, and 2.0,, each have their quirks and advantages.
Often when I just want to throw a 50mm in my pocket, it is the 2.0 or 1.8D just because both are so small and light, that you don't know they are there, until you need them.
as far as sharpness, they are all sharp except perhaps the 1.2,, but the 1.2 can create dreamy photos, and mechanically..... ah perfection.
and for disclosure, I have a bias against G lens,, unless in the larger tele (because at that point the extra area penalty is buried in the overall size of the lens anyway).