I'd narrowly rate Montoya the best I think. His form across 2021 was outstanding.
Mbonambi, Marx and LCD probably the next tier just behind. Then Codie Taylor and Julien Marchand - who's improved remarkably in the last 18 months or so - also thereabouts. I think Montoya consistently has the biggest impact of the lot though. Marx has a huge impact in the final 30 minutes playing that substitute role for the Boks but I still don't think it quite matches Montoya across a match.
Gianmarco Lucchesi isn't playing in a great Italy pack but could certainly get up there with the best hookers in a couple of years if he continues his current trajectory as well. For an inexperienced 21-year-old hooker he has been very good indeed at times.
There are a lot of really good hookers in international rugby at the minute basically and Montoya has a very good argument for being the best of the lot. A player I hope to see at Tigers for years to come.