Asking for members blessings on Nagaoka MP 300 purchase

So they have a lightly used MP 500, which I believe was a return with very few hrs. I actually can get it for less than the MP 300 new. The 300 is supposed to be a bit warmer, but will does up some detail to the 500. And my understanding is the 300 is a bit more forgiving of less than perfect VTA setup. So it's certainly not the money. It's more about a bit more warmth and allowing the slight margin for error with less than prefect setup. Funny... of all the Nags, I found the least amount of info on the 300. I think that's because most who can shell out for the 300 stretch a few more bucks and get the 500. 

Unless you really know the provenance of the used MP500, I’d advise you to suck it up and buy a new MP500. 

Solid advice on a solid line of cartridges.

The upper Nagaoka line tends to offer incredible midrange clarity and soundstage, along with excellent dynamics.  The MP500 has the same body as the MP300, but offers the upgrade of a line contact stylus vs elliptical, which tracks better and gives a more delicately detailed treble, with better space and air than an elliptical. As others have suggested, opt for the 500.

Agreed that the MP-500 is desirable, mine outperforms my Grado Statement 3 and my Soundsmith Sussurro MkII. It is very close to my London Decca Reference. I can't say anything better than that!