best cartridge under $500

Agree with Doug with a single caveat. IME there are a handful of moving coils under $2K that are just as enjoyable or perhaps more than some of these excellent moving magnets. Zyx Airy 3 being one example.

However, I'm a big moving magnet fan and almost 50% of my cartridges are moving magnet/iron. Cut my teeth on the original Shure V-15 (old fart). They are by leaps and bounds much better values than moving coils. No contest.

For the past month or so I've spent a fair amount of time with these moving magnets:
ADM-TRX-2
Audio Technica ATN-150MLX
Audio Technica AM-30s
Signet TK7SU

I owned the Signet back in 1977 and parted with it foolishly. Recently came across an NOS and jumped at it. They are very difficult to find (NOS stylus almost impossible) but simply one of the finest cartridges I've heard/owned. If you find one buy it or email me.

It's stunning how wonderful many moving magnets sound.

No financial interest involved

I am a moving coil user but with the SME I would use MM, they are a better fit for the characteristics of the arm; they are the type of cartridge it was designed to use.There are many choices, I like the contemporary Ortofon "color" line up but NOS is also good.

I'm using a Jolida JD-9 Tube Phono Preamp to a mcintosh c-30 preamp
Jon

The Ortofon 2M series (moving magnet) are very good,especially for the money!I use a Blue on one of my vintage Dual tables.The sound is incredibly good,much better than the OM30 Super it replaced.The 2M cartridges are easy to mount as well.I find the "Bronze" to be the sweet spot in the line-up.It can be purchased under your budget limit.

Ortofon Black 2M great cart with a lot of favorable reviews. around 650 new