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, accidental clicks when slamming down the mouse do not occur.

Buttons

Main buttons on the M800 Ultra are very good to excellent. Pre-travel is low and post-travel moderate to low, resulting in a firm and snappy button response. Despite being visually separated from the shell, button movement is minimal even when provoked. Button stiffness is medium to low. A pair of Huano switches (blue shell, pink plunger, 80 M) are used.


Side buttons are good (forward button) to very good (back button). Whereas pre and post-travel are low on the back button, the forward one has moderate levels of pre and post-travel. The actuation point is even across the entirety of these. Button size and placement are quite good, as actuation is possible rather easily by rolling one's thumb across. A set of Huano switches (white plunger) are used for these.

At the bottom of the mouse is a button for cycling through the set CPI levels, which works just fine, accompanied by another button for cycling through polling rates, which too works fine. 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 subpar. Scrolling is very noisy, and tactility below average, as the steps mostly lack separation. The encoder comes from F-Switch (gray, cyan core) and has a height of 11 mm. The middle (scroll wheel) click requires medium to high force for actuation. An elevated Huano switch (red plunger) is used for this one.

Surface

The M800 Ultra 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 M800 Ultra is easy. First, the front and rear skates and the two screws each beneath them need to be removed. In addition, the sides are locked in with several clips, dislodging which is best done by wedging something like a credit card in. When separating top and bottom, make sure not to rip the cable connecting the two.

The internal design is simple. The side buttons sit on their own PCB screwed to the top shell and are connected through a ribbon cable to the main PCB, whereas the battery sits on a sticky pad in the rear. Three screws are used to affix the very thin main PCB to the bottom shell. The MCU is a Nordic nRF52840, whose datasheet is found here.


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