Just wondered what with the NGX and 777 being highly realistic representations of the real aircraft, on what level does the old 747 stand?

I would say the 747 is still a decent aircraft. The textures are not as crisp, there are no FS actions shortcuts in the FMC, and the sounds are comparatively lacking (all three of which are significantly better in the MD-11 I would say). The systems seem up there, though failures are comparatively limited. No service-based failures to speak of.