I tried the first prototypes he made, few years ago.
Those are the mouthpiece were base on the same blank Mojo used for his "Vortex" pieces.
I didn't like the finishing (they were just "blank"), I didn't like the material and the form factory (the mouthpiece had a very "squared" frontal sections, which is not the best thing for the lips: you get tired pretty fast, compared to most standard piace which have a more "oval" frontal section for the beak).
The sound was pretty "rock'n'roll" to me, to be considered a "jazz mouthpiece".
(These were the old piece!)
I tried a couple of pieces a month ago, the new ones... and the improvement is massive.
It's unusual to see mouthpiece for a "tight clear" sound nowadays, on the market... but now the mouthpieces are well made, well finished, really easy to play... pretty cheap too!
It's still somewhat annoying for me (personal preference!) to have a such a small (tenor) mouthpiece in mouth... but it's very subjective.
The ligature problem... is actually still a problem here.
Rovners fit great and work great... but here in Italy it's almost impossibile to find a Rovner 1M/L11 (for the tenor model).
P.S.: Carlo is a monster player, a real hard bopper.