I think the biggest difference that time makes (comparing old camera in good condition to new camera) is the sensor.
Yes, AF systems get (lots) better over time, and that may or may not be a factor depending on the type of images you're trying to capture. But sensors from >10 years ago had a lot more noise than today's sensors. If you're shooting in good light (and can therefore use lower ISO speeds), then you'll probably be happy. Going over 400 back then was questionable. Using 1600 in today's cameras is really no big deal. Even with higher ISO speeds where noise starts to creep in, the noise is "less obnoxious" than in older systems. In many of today's cameras you can shoot with higher ISO speeds.
Good light? Good pictures.
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