Why a mk4s instead of a Core One?
There’s a lot of right answers, but a QIDI or a Core One would probably be my two options here.
You mentioned an IDEX, are you interested in multi material, like combining PLA and PVA, or are you interested in multi color, like with an MMU?
Core One has a slightly larger print surface, and the enclosure means it can print more advanced materials.
Prusa is likely going to continue building off the core platform, so it’ll probably be more upgradable than the mk4s.
Also, I think it looks nicer, like an appliance instead of a project.