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.

Buttons

Main buttons on the Harpe Ace are very good. Pre-travel is low and post-travel moderate, resulting in a firm and snappy button response. The buttons aren't entirely uniform, however, as the right one sounds duller than the left. While the buttons are visually separated from the shell, lateral button movement is minimal and cannot even be provoked. Button stiffness is medium. ROG Micro Switches (70 M) are used.


Side buttons are good (back button) to very good (forward button). Post-travel is low on either, but the back button has significant pre-travel, and therefore feels mushier than the firm forward button. Button size and placement are quite good, as actuation is possible rather easily by rolling one's thumb across. A set of surface-mounted switches from Kailh (yellow plunger) is used for these.

At the bottom of the mouse is a CPI button, used for cycling through the set CPI steps. Its click feel is decent. A seemingly unbranded tactile switch is used here. In addition, another button for pairing the device with a wireless receiver is found on the bottom, which too utilizes a seemingly unbranded tactile switch, along with a slider that switches between off-state, Bluetooth, and 2.4 GHz wireless, both of which work without issue.

Scroll Wheel

The scroll wheel is very good. Noise levels are somewhat elevated, but tactility is very good, with clearly separated steps allowing for controlled scrolling. The encoder comes from TTC (yellow) and has a height of 12 mm. The middle (scroll wheel) click requires medium to low force for actuation. A seemingly unbranded tactile switch is used for this one.

Surface

While the sides have a shallow line pattern, the rest of the shell features a rougher matte surface. Compared to common ABS plastic, the surface feels grainier and coarser. Grip is fine, and 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 Harpe Ace is easy. Only the two rear skates and the screws beneath them need to be removed. The top and bottom shell are then readily separated.

The internal design is fairly straightforward. The side buttons sit on their own PCB vertically slotting into a plastic array part of the bottom shell. An auxiliary PCB next to the scroll wheel provides wheel illumination. Both PCBs are connected to the main PCB with a singular FFC (flat flexible cable). The battery is positioned towards the back of the mouse for better weight balance. Four screws are used to affix the thin and fairly compact main PCB to the bottom shell. The MCU is a Nordic nRF52840, whose datasheet can be found here. Curiously, the markings of the CPI and pair button are flipped on the PCB.


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