Which is better, the Sony A7C II or a7 IV?

For most buyers choosing today, the Sony A7C II is the better pick if you want the smallest full-frame body with newer autofocus. Choose the Sony a7 IV if you prefer a bigger, more comfortable body, dual card slots, fuller controls, and a better viewfinder/handling setup for paid work or long shoots.

Quick verdict: A7C II for travel, everyday hybrid shooting, and compact kits; a7 IV for events, professional backup workflow, and ergonomics.