Just chiming in because I recently did work on both a Grado Prestige Gold stylus and a recent issue 8MZ stylus. Both have the same diamonds. The 8MZ has a focus on lower mass for better tracking. To that end, the cantilever is slightly narrower and the generator is obviously smaller because it puts out 2/3 the voltage of the Prestige Gold cartridge. This should lead to better tracking due to lower moving mass.
In listening, the 8MZ is a tad brighter and much lower volume. Details are plentiful and clean. All other Grado goodies are present in full.
The Gold stylus is a bit more mellow in comparison, plenty of detail but not quite as crisp. Also louder.
Difficult to say which one I actually prefer, but I think I like the more laid back Gold. I did not try the styli in a Signature body to see if there would be any difference. These were tried in a Gold2 body.