indeed i shall
A very good friend of mine, Shawn, owned an extremely nice 300 several years back. Got it at a good price, with low km's and looked very clean. So my experience stems from him and his fellow 300ZX's that I met.
You point about it being a great car "new" is completely invalid as anybody who's buying this car is buying a 15yo (or more!) hand me down. The reason this car is very bad is because in it doesn't age very well. Compared to other imports of the same era they seem to be more prone to parts failing, consistently.
For some reason, they also seem to be very expensive to fix, not to the point of a GTO, but still very expensive considering the alternatives.
It MAY have been a nice car, but in my opinion it is no longer is a viable option when choosing an import in todays market.