Build Quality

Overall build quality is mostly solid. When shaking the mouse, a slight rattle comes from the main buttons. When applying lateral pressure, minor creaking can be observed, and the sides have some flex. Activating the side buttons by squeezing the sides is possible by applying moderate pressure. Lastly, accidental clicks do not occur when slamming down the mouse, regardless of the set debounce time.

Buttons

Main buttons on the M3 4K are good to very good. Pre-travel is moderate, but post-travel fairly low, resulting in a rather firm and snappy button response. While the buttons are visually separated from the shell, lateral button movement is minimal and needs to be provoked. Button stiffness is medium. A pair of TTC Gold (60 M) switches are used for these.


Side buttons are very good. Pre-travel is low and post-travel moderate (more so on the back button), resulting in a snappy and pleasing button response. The pressure point is even across the entirety of these. Button size and placement are good, as actuation is possible rather easily by rolling one's thumb across. A set of TTC switches (red plunger) is used here.

At the bottom of the mouse is a button for cycling through the set CPI levels, which works just fine. A seemingly unbranded tactile switch is used for this one. An additional button cycles through the available polling rates, which too works fine. Another seemingly unbranded tactile switch is used for this one. Lastly, a slider at the bottom switches between 2.4 GHz operation, Bluetooth, and off-state, which also works fine.

Scroll Wheel

The scroll wheel is good. Noise levels are mostly under control, but tactility is little more than decent, providing moderately distinct step and mostly controlled scrolling. The encoder comes from TTC (yellow or "gold") and has a height of 10 mm. The middle (scroll wheel) click requires high force for actuation. Another switch from TTC (purple plunger) is used for this one.

Surface

The M3 4K has a matte surface all over. Grip is fine, and it doesn't attract fingerprints or dirt too much. It is easy to clean, and there are no signs of wear left after doing so. All in all, excellent materials.

Button Sound Test

Disassembly

Disassembling the M3 4K is easy. The screws are located beneath the front and rear skates. The sides are additionally locked in with clips, dislodging which is best done by wedging in a credit card or something similar. When separating the top and bottom shell, make sure not to rip the cable connecting both.

The design is very straightforward. The side buttons sit on their own PCB screwed to the top shell and connected through a ribbon cable. Everything else sits on the large and fairly thin main PCB, which is affixed to the bottom by four screws. The battery is stuck to the dongle storage compartment. The MCU is a Nordic nRF52840, whose datasheet is found here. Production date for the side-button PCB is the 14th week of 2023.


As for the soldering and general quality of the PCB, I'm unable to find any noteworthy flaws.