My first MC was an Ortofon MC20 with an Ortofon head amp back in the late '70s. Since then I've only strayed a couple of times - with Grado Signatures. Prior to the MC20 I had used a Shure V15III, a Stanton 6181EEE, a top of the line Pickering, an ADC, and an Audio Technica (AT-15??, the early Shibata cart.) I also sold Signets, B&Os, Grados, the Grace F9E, and I forget what else. On the MC side I had the privelege of selling and hence hearing most of the top MCs of the '80s (Denons, Argent, GAS, Koetsu, Fidelity Research, Talisman, Supex,...)
What sold me was playing the War of the Worlds lp (Jeff Wayne). When the Martians landed and the capsule opened, the opening sound (made with cymbals) sounded like metal for the first time. Nothing else that I had heard to that point of time resolved the sound as well.