Build Quality

Overall build quality is very solid. There is no rattle when shaking the mouse. When applying lateral pressure, no creaking of the shell can be observed. It is impossible to activate the side buttons by squeezing the sides with any amount of force. Lastly, no accidental clicks occur when slamming the mouse down.

Buttons

Main buttons on the A660 are excellent. Pre-travel is very low and post-travel low, resulting in a firm and satisfying button response. The main buttons are separated from the shell, but only very minor button movement can be provoked. Button stiffness is light. Omron D2FC-F-7N (20M) (OF) switches are used here.


Side buttons are very good. There is some pre-travel, but post-travel is low. The pressure point is mostly even, but click feel is a bit dull. Button size and placement are good as actuation is possible rather easily by rolling one's thumb over these. That having been said, I did end up unintentionally actuating these quite a few times during play. I have the same issue with the Logitech G203/305, so I'm not sure whether this is a design flaw or due to my grip. Two unbranded tactile switches are used for these.

At the top of the mouse is a button for modifying the RGB modes. Its click feel is decent. An unbranded tactile switch is used here. At the bottom, two sliders can be found: one for changing CPI levels and the other for adjusting the polling rate. Both of these work just fine.

Scroll Wheel

The scroll wheel is very good. Tactility is a bit lacking for my taste, but neither scrolling up or down produces any unwanted noise. The encoder comes from TTC. The middle scroll wheel click requires high force for actuation. A YSA switch (red plunger) is used for this one.

Coating

While the sides are smoothed ABS plastic, the top has a matte UV coating. It's very grippy and doesn't attract fingerprints, dirt, or the likes too much. It's easy to clean, and there are no signs of wear left after doing so. All in all, an excellent coating.

Button Sound Test

Disassembly

Disassembling the A660 is very easy. Just remove the bottom mouse skate and unscrew the screw beneath, which has the top shell come off with ease. The internal design is somewhat unusual. There are two PCBs: a side-button PCB, which holds the side buttons, the top RGB button, and the LED for scroll wheel illumination, and the main PCB, which holds everything else. The side-button PCB is mounted on two pillars. That way, the buttons can actuate the switches directly. A ribbon cable connects the side-button and main PCB. Three screws are used to affix the main PCB to the bottom shell. Both PCBs are moderately thick. Production date for the side-button PCB is May 25, 2017, whereas it is October 23, 2017 for the main PCB. Interestingly, the A660 uses a different MCU from the Abkoncore A530: a Bayi BY8832, which we also saw used in the Dream Machines DM4 Evo.


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