Time for a new MM cartridge

First, the Grado Reference and the Reference Platinum are moving iron (MI) type cartridges, not MM.  So if you really like those two, you might consider specifically hunting for another MI type, maybe move up the Grado line.  Otherwise, from what I have been able to tell, the Nagaoka's get better as you move up their product line, so you might consider the best Nag you can afford.  And finally, your other choices are excellent too.  The AT has gotten many favorable comments on line.  You will likely get dozens of different advisories here, but you won't go wrong with any on your existing list, either.

I have a Nagaoka MP-200. Superb cartridge in it's price range.

I’m guilty as charged on lumping MI in with MM.😉 The current version Grado Reference is more than I care to spend at today’s pricing. I like the sound of the Grados, but looking to branch out a bit.

On another note; I received my Flux Hifi ultrasonic stylus cleaner last night. Used it for first time this morning (after my post), and it breathed a bit of life back into the Reference. I thought my regimen of Onzow and stylus brush was adequate, but the Flux seems to improve on that significantly. I'll still add a second/new cartridge.

I mentioned the MI type, because I personally have a predilection for that type, although I own and enjoy cartridges of all 3 major types.  On the other hand, the last Grado I owned was a TLZ, back in the 80s, which I enjoyed for many years as my only cartridge.

mr m. 

the Nag 200 is superb in any price range .