Build Quality

Overall build quality is very solid. When shaking the mouse, a very minor rattle comes from the side buttons. 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 Prime are good to very good. Pre and post-travel is moderate on the left button, whereas the right one has low pre-travel and moderate post-travel. Button response is firm, yet weirdly muted, lacking feedback almost entirely. In a way, they almost feel like tactile switches. Despite being visually separated from the shell, lateral button movement is as low as physically possible and cannot be provoked either. Button stiffness is medium. SteelSeries-branded Prestige OM switches are used.


Side buttons are excellent. Both pre and post-travel are virtually nonexistent, resulting in a very firm and snappy button response, further complemented by the pressure point being perfectly even across the entirety of these. Button placement is good as actuation is possible quite easily by rolling one's thumb across. A set of Kailh switches (grayish case, red plunger) is used.

At the bottom of the mouse is a single button for cycling through the set CPI steps and polling rates. How this works isn't immediately obvious. In order to cycle CPI, one has to press the button once to enter CPI mode, and only then is it possible to cycle through the set CPI steps with further button presses. Similarly, pressing and holding the button cycles through the available polling rates, going from highest to lowest. A seemingly unbranded tactile switch is used for this one.

Scroll Wheel

The scroll wheel is good to very good. Scrolling in either direction is really noisy, but tactility is on point, with clearly discernible steps and a matching tactile feel when scrolling. The encoder comes from TTC (black core) and has a height of 12.6 mm. The middle (scroll wheel) click requires medium force for actuation. A seemingly unbranded tactile switch is used here.

Coating

The Prime has a slightly rougher matte surface all over. Grip is fine, but it does pick up fingerprints, dirt, and the likes quite easily. It is easy to clean, and there are barely any signs of wear left after doing so. All in all, good materials.

Button Sound Test

Disassembly

Disassembling the Prime isn't too difficult. The biggest hurdle consists of the four Torx T6 screws located beneath the three skates. With those taken care of, top and bottom shell are easy to separate. While the main button switches are part of the top shell and insert into two contact points on the PCB, the side buttons sit on their own PCB screwed into the top shell and connected to the main PCB through a ribbon cable. An auxiliary PCB next to the scroll wheel provides wheel illumination. Four screws in total are used to affix the fairly thin and compact main PCB to the bottom shell. The MCU is located on the bottom of the main PCB. An STM32F103CBT6 is used, whose datasheet can be found here.


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