Build Quality

Overall build quality is very solid. There is no rattle when shaking the mouse. When applying lateral pressure, no creaking or flexing of the shell can be observed. Activating the side buttons by squeezing the sides is impossible. Lastly, no accidental clicks occur when slamming down the mouse, unless a button response time of 1 ms is chosen within the software.

Buttons

Main buttons on the MM731 are very good. Both pre and post-travel are low, resulting in a firm and snappy button response. In terms of click feel, the right button comes across as duller and more muted than the left one. Button stiffness is medium to light. Despite being visually separate from the shell, lateral button movement is low and needs to be provoked; i.e., is not noticeable during typical use. A set of LK V2 optical switches is used here.


Side buttons are very good. Pre-travel is low, resulting in a snappy button response, but the buttons can be pushed in quite a bit past the actuation point. The pressure point is even across the entirety of these. Button placement is great as actuation is possible very easily by rolling one's thumb across. A pair of Huano switches (green plunger) is used here.

At the bottom of the mouse is a single button for cycling through the set CPI steps, which works just fine. A seemingly unbranded tactile switch is used for this one. Furthermore, a slider on the bottom toggles between Bluetooth, 2.4 GHz, and off-state, which too works fine.

Scroll Wheel

The scroll wheel is excellent. Noise levels are appreciably low, and tactility is great, with clearly discernible steps and a matching tactile feel when scrolling without being overly stiff. The encoder comes from Kailh (black core) and has a height of 13 mm. The middle (scroll wheel) click requires high force for actuation. Another Huano switch (green plunger) is used for this one.

Coating

The MM731 has a smooth matte surface all over. It doesn't attract fingerprints, dirt, or the likes 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 MM731 is easy. Remove the two rear skates and the screws beneath them and the top will come off with ease. The internal design is very efficient. Except for the side-button PCB screwed into the top shell and connected through a 3-pin connector, everything else sits on the main PCB. Curiously, just two screws are used to affix the main PCB to the bottom shell, which is why it can be lifted at the front without issue when disassembled. Yet, when assembled, a support column from the top shell pushes down on the PCB, providing the necessary stabilization. We can also see that the sensor is placed as far forward as physically possible. All PCBs are very thin to save as much weight as possible. The MCU is a Nordic nRF52833, whose datasheet can be found here.


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