it was worth the jump for me, but this is not so simple a question.
my local friend @jazdoc owns the Zero, and the Sumile mono. maybe he will chime in. i have heard both in his system; the Zero was excellent, now the Sumile mono is awesome there.
my perspective is that where you need to be on a mono cartridge comes down to one significant issue beyond assumed serious interest in mono pressings.
your stereo cartridge performance on mono pressings. how does it do?
this one is hard to qualify unless you already have a mono cartridge for reference. in my case for years i first owned a Miyajima Premium BE mono. a nice solid mono cartridge. made my mono pressings better. as my stereo cartridge performance improved, and their mono pressing performance improved, i decided to buy two Miyajima Infinity carts; one .7 stylus version, and one 1.0 stylus version and have both choices for various mono pressings. i do have maybe 30-40 wide groove mono pressings and hoped that would be optimal. and it was. but after a few years the improvement of my stereo cartridges caused me to again use them with my mono pressings. the advantages of the Infinity on mono pressings became trade-offs. the stereo carts were more refined. which then caused me to then sell the Infinity’s and buy the Sumile Mono.
now the Sumile mono matches the refinement and sexy bass of my stereo carts, and also adds the better lively presentation and mono directness.
so this is not any objective easy call. it’s all about the relative quality of your stereo cartridge performance on mono pressings. and you have to play a variety of mono pressings on both to really get a feel for how it works. the Zero or Infinity are both great mono carts, and it will take a quite amazing stereo cartridge/arm combo to surpass/equal either. but that can happen.
and the arm you place the mono cartridge on is also part of the equation when judging this compare.


