Logitech MX Master 4S Review: Fifteen Years On, Still Unbeaten

The MX Master line is fifteen years old. The ergonomic form factor — right-handed thumb rest, horizontal scroll wheel, high-arched profile — was established in the first generation and has been refined rather than reinvented in every subsequent one. The MX Master 4S continues this tradition.

What’s new: the primary sensor upgrades to 8,000 DPI with improved tracking on glass surfaces. The MagSpeed wheel now supports three modes — ratchet, free-spin, and the new haptic mode that simulates discrete clicks through vibration rather than mechanical stops, which is a useful option for quiet environments. Bluetooth connectivity has been upgraded to Bluetooth 5.4, with noticeably improved connection stability when switching between devices.

Battery life remains 70 days on a full charge, unchanged from the MX Master 3S. USB-C charging. The build quality, as always, is excellent — this is a mouse that feels like it will last a decade, because in my experience MX Master mice do.

The score is a 8.7 rather than higher because at $129 the price is steep for a mouse and the improvements over the MX Master 3S are real but incremental. If you own a 3S, upgrade only if the glass tracking or the haptic scroll wheel specifically matters to you. If you don’t own any MX Master, the 4S is the best productivity mouse available without qualification.