Why we chose this
We've shipped four years of work through MX Master mice and never once thought 'I wish I had a different mouse.' The Master 4 is a quiet refinement — better thumb haptics, longer battery, better cross-machine flow — that earns the upgrade without reinventing what already worked.
The review
The MX Master line has been the default 'good mouse' for power users since 2015, and the Master 4 keeps that crown while finally addressing the small ergonomic complaints that have nagged the series. The thumb rest now has a configurable haptic actuator — discrete clicks for application switching, scroll-end detents on long pages, even rhythmic pulses when a timer fires — and Logitech's new Smart Actions engine lets you trigger app-specific macros without leaving the mouse. The MagSpeed scroll wheel remains the best in the industry (it can hyper-spin a thousand lines a second and stop on a dime), and the rechargeable battery now lasts a claimed 90 days per charge in typical use. Cross-computer Flow control works across three machines, drag-and-drop transfers files between them, and the USB-C port is finally on top rather than the front — small but it makes hot-swapping between charging and using a non-issue.
