I have never heard a high quality mono cartridge, but I would like to. (I think Ortofon lists a mono stylus for their OM series cartridges--they also have a 78 stylus for these cartridges.) I found Shure 78E stereo stylus at a yard sale. I asked on the Audioasylum why stereo for 78's, and the answer I received from someone was that often one channel will sound much cleaner than the other. (Having a old school pre-amp that allows each channel input to output to both channels is needed for this of course.) This of course is more of an issue with noisy 78's than with mono lp's, but it is consideration. I have a Citation 1 preamp with all the switching and filter slopes one should need for all record playback, but it needs work so I haven't tried it yet.