Nice to have the ATS option! Schlumpf is well regarded quality. Efneo is less common, but it has been around a while by now. It got a very good review in road.cc in 2017.
https://road.cc/content/review/22779...-front-gearbox

I am considering it for another bike, but there the lack of any option between 28t and 38t is a bit of a problem.