Aftermarket styli vary enormously in price and some are outright bad. The Japanese Jico ones have a good reputation. Shure themselves recommend their M97xE cartridge as the best replacement.
As an anecdote, I recently noticed that the audio archive of the British Library use the Shure M44 cartridge for their digitization of some old recordings, using specialty styli: https://www.youtube.com/watch?v=yI5DYJPSf-A&feature=youtu.be&t=162
As an anecdote, I recently noticed that the audio archive of the British Library use the Shure M44 cartridge for their digitization of some old recordings, using specialty styli: https://www.youtube.com/watch?v=yI5DYJPSf-A&feature=youtu.be&t=162