What airlines do you most frequent? Travel itineraries? It is a usual case of "it depends".

If international flights are the majority of flights, you'll have no problem fitting a Hybrid M into widebody overhead bin space. Notice, the Hybrid M DOES EXCEED most carriers' carry-on dimension restrictions.

However, if you are traveling LCC or domestic /short-haul routes, you are better off with the Hybrid S due to the smaller overhead bin size on narrowbody and smaller airframes. The Hybrid S also exceeds many carriers' carry-on dimensions, this will matter if you frequent the likes of easyJet or RyanAir.