I recently upgraded to the Logitech MX Master 4 Wireless Mouse in Graphite and it has quickly become one of the best productivity peripherals I’ve used. The ergonomics are excellent for long workdays, especially when moving between CAD drawings, spreadsheets, browser tabs, and remote sessions. The shape feels natural in the hand and significantly reduces fatigue compared to standard office mice.
The MagSpeed scroll wheel is exceptionally smooth and precise, and the side scroll wheel is a major advantage when working with large timelines or wide spreadsheets. Logitech also did a great job refining the Quiet Click buttons — the mouse feels premium without adding unnecessary noise in an office environment.
The new haptic feedback and customization options through Logi Options+ add another level of workflow efficiency. Switching between multiple computers is seamless, and the tracking performance works flawlessly even on glass surfaces. Battery life has also been outstanding.
Overall, the Graphite finish looks professional and holds up well to daily use. If your work depends on productivity, multitasking, or precision navigation, the MX Master 4 is absolutely worth the investment. 
As a previous user of the MX Master 3S, I can confidently say that the MX Master 4 is on a whole different level. I am extremely satisfied with this purchase! Premium Innovation: The new haptic feedback system gives a fantastic tactile response that makes scrolling and navigating intuitive. Actions Ring: This new button feature is a game-changer, giving instant access to shortcuts directly at your cursor and saving massive amounts of time. Superior Build: The materials feel much more premium and solid in the hand compared to older generations. It is smooth, whisper-quiet, and provides the ultimate navigation experience. 100% recommended for any professional!
I switched to MX Master 4 from the 3s due to click button problem. Comparing to the 3s, 4 is heavier. The material is also more desirable for me as I don't really like rubber-stick-ness in my hand. Controling is much better with weight. I am in academic, so heavier the better control. Short key buttons are also convenient.
The mouse is well built and works well but the "thumb button" and vibrating rest pad have been annoying.After trying to adjust to it for a few weeks, I turned it off but the pad still lightly vibrates when pressure applied. I had the MX Master 3 before and hoped this might be an improvement but that spring loaded pad and vibration have been very distracting. I do like that added features with the latest Logi Options software.
And not only would I for-sure favorite the debut single from MX Master Mouse on Spotify, it's also a damned good input device for my PC. It's comfortable, fits beautifully in my hand, and has a lot of features that I love (especially the MagSpeed scrolling). I still accidentally click the thumb-triggered "Action ring" when I don't mean to, but turning the sensitivity down has helped with that. I need to spend some time setting the action ring up and getting used to it. I'm sure it's great but I just haven't used it much. Anyhoo, in summary, I've been using MX Master mouses since v2 and I love them. I wouldn't call an upgrade from v3 to v4 a necessity, but I bought one for home and one for work so I guess you could say they're my favorite. A++++++ 10/10 Would recommend.