Best MM?

Now I know who is brainwashed. Get out of here.

What was the cost of the IQ3 and where did you get it ? New, I assume, correct ?

Unless I am wrong Audio Note IQ MM is a refined Goldring 1042. I use this Goldring with Nottingham table/arm.

Vortrex, thank you. No, I am not going to replace my Goldring 1042 right now. $1000 is a lot of money in my book, besides I like some edginess in the sound, Audio Note might be too refined for my taste. No way to know, though, unless you try.
Nagaoka MP500 and the Audio Note cost about the same. I never really think German when it comes to analog.

Anyway, best MM doesn't exist. It's a matter of particular set up and taste.

I've been saying it. Goldring 1042 is the best value, in addition to some vintage perhaps, it is under $400 from the UK. Save your funds for a real good phono and tonearm cable.

My question was exploratory, I have no intention to replace the Goldring for as long as I hear improvements in sound whenever I make changes somewhere else in the chain. Until the time comes to replace the stylus. Then I might try different cartridge and I might not.
The entire system must be in balance and tuned to one's liking. Besides, higher resolution cartridge will require better phono stage which in turn must blend in well with the rest.
Before choosing the Goldring I was thinking about Grado reference but decided to go with the former mostly because Nottingham cartridges, no longer made I understand, were customized Goldring, but also because Goldring 1042 seemed popular in the UK. I also read that Grado can be foggy. I like Grado headphone sound, but yes it is somewhat foggy. My turntable is on a warmer side, so are the speakers. I think, the Goldring fits right in, it is too on the warm side of neutral but not much and is quite dynamic and engaging, like Nottingham Spacedeck turntable.

I would have to go thru possibly dozens of vintage cartridges to determine which one I like most with Nottingham table/arm. It is such a pain to change cartridges in that arm because the wires are so thin. Besides, I would have to have them all at the same time. 
Stating that any particular vintage cartridge would sound better in any set-up for any taste is not quite right.
Chakster, which vintage cartridge would you recommend for me if you are familiar with Nottingham ? $400 or $1000 no difference if it's worth it.

I am sure that MC people will profoundly disagree. I am also sure that some of them tried many both MM and MC cartridges from all time periods. I am very neutral in this debate and couldn't care less about which ones are better or just different. But let's cut BS, anyone I have heard of who has truly high-end set up uses MCs. Certainly there might be many others I haven't heard of who prefer MMs, vintage or not. It is also hard just by reading posts to figure out who has'got good hearing and who has not. Hard but not always impossible. And no sales pitches, please.

Calling them brainwashed imbeciles is a bold statement and an insult, unless you can prove it. You did say "we all", though. Who is we ?

Some kind who studies people not cartridges.