For the past two years, Glorious has been going through a slope when it comes to mouse releases. Compared to what the competition had to offer, releases such as the Model O 2 Wireless or Model I simply weren't up to par. With the Model O 2 Pro 4K/8KHz Edition, however, Glorious once again has a fully competitive product in their line-up. In some way, it even is ahead of most competitors, which typically only offer polling rates above 1000 Hz in wireless operation, whereas the Model O 2 Pro 4K/8KHz Edition also allows up to 8000 Hz in wired operation. Most competitors choose against doing this, as polling rates above 1000 Hz in wired operation require a secondary MCU on the mouse PCB providing a USB high-speed PHY, which increases weight and drives cost. Accordingly, the Model O 2 Pro 4K/8KHz Edition lands somewhere between the price ranges invoiced by competitors: At $129.99, it costs more than the $100 range releases from LAMZU or Pulsar, but less than the Logitech G Pro X Superlight 2 at $159.99 or Razer Viper V2 Pro at $149.99, with an additional $29.99 for their HyperPolling Wireless Dongle.

In terms of weight, the Model O 2 Pro 4K/8KHz Edition compares favorably regardless. At 59 g, the Model O 2 Pro 4K/8KHz Edition essentially is on par with the Viper V2 Pro, while too doing entirely without visible holes or an open-bottom design, and at a comparable (arguably even larger) size. In terms of shape and size, the Model O 2 Pro 4K/8KHz Edition moves away from the Model O 2 Wireless and instead approaches the Model O Wireless once again, as the main buttons are not framed by ledges, though the Model O 2 Pro 4K/8KHz Edition also ends up being slightly longer than either of its predecessors. In terms of build quality, my sample is spotless. There is no rattle when shaking, applying lateral pressure only results in minor creaking but no flexing of the shell, and the side buttons cannot be actuated by pressing below them regardless of how much force is applied.

Another novelty of the Model O 2 Pro 4K/8KHz Edition are the main buttons. Thus far, Glorious exclusively used mechanical switches for their main buttons, combined with defer-type debouncing. The issue with this approach is as follows: As the mechanical switch ages over time, bouncing becomes more prevalent, requiring one to filter out unwanted inputs, i.e., debouncing. Defer-type debouncing is quite effective at that, but does increase click latency in the process. Hence, in order to combat continually increasing inadvertent double-clicking, one has to up debounce time, resulting in click latency going up as well. In addition, even out of the box, slam-clicking, which describes inadvertent button actuation upon resetting the mouse after lift-off, was also common when using the lowest debounce time setting. On the Model O 2 Pro 4K/8KHz Edition, Glorious addresses this situation from multiple angles. Firstly, the main buttons are outfitted with optical switches from RAESHA, which have also seen use on recent releases from Pulsar and LAMZU. By virtue of not bouncing in the first place, these switches do not require debouncing, which is why the lowest debounce time of 0 ms can be used without running the risk of double-clicking. Second, slam-click prevention has been implemented, so that the lowest debounce time in fact can be used all the time without any drawbacks. That is, in theory at least, since the set debounce time applies to all buttons indiscriminately. Hence, when set to 0 ms, the main buttons won't double-click, but the side buttons or scroll wheel click will, as these still utilize regular mechanical switches. This, of course, begs the question of why Glorious doesn't restrict this setting to everything but the main buttons, as those can be run at 0 ms no matter what.

In terms of button response, the optical switches do quite well. There is some pre-travel, but post-travel is low, and actuation rather firm and snappy. In addition, lateral movement is rather low, and only becomes noticeable at all if explicitly provoked. For the side buttons, Glorious utilizes surface-mounted mechanical switches from Huano, with mixed results. While the forward button shines with low pre and post-travel, the back button suffers from both uneven actuation and moderate pre-travel. The scroll wheel encoder comes from F-Switch, and of particular note with this model are the low noise levels. Tactility, on the other hand, is merely above average, as the individual steps aren't particularly well-separated from each other. The feet have received no changes over previous iterations of the Model O, are still made of pure PTFE, and still glide well.

On the Model O 2 Pro 4K/8KHz Edition, PixArt's PAW3395 sensor is paired with two MCUs. First, a Nordic nRF52840 is used for wireless communication, which is restricted to regular USB full-speed. Second, a USB high-speed MCU from WCH sees use, which, unlike most other MCUs used for mice, utilizes the RISC-V ISA instead of Arm. When it comes to latency, the Model O 2 Pro 4K/8KHz Edition doesn't disappoint. In wired mode, click latency at 0 ms debounce time is the same regardless of polling rate, and comes out at a respectable 0.4 ms. In wireless operation, polling rate does have an effect, and click latency at 0 ms debounce time varies from 1.1 ms at 1000 Hz all the way down to 0.6 ms at 4000 Hz, which is up there with the best from Razer or G-Wolves. Motion delay likewise is on an excellent level: In wired operation, the Model O 2 Pro 4K/8KHz Edition is ahead of the Logitech G403 (control subject) by roughly 1 ms regardless of polling rate, though this only applies with MotionSync disabled, enabling which adds various amounts of latency and thus is best avoided. In wireless mode at 4000 Hz, motion delay is only marginally worse at an advantage of 0.7 ms over the G403, though MotionSync once again is better left disabled due to the latency added by it. When it comes to polling stability, results are mixed. Polling rates above 1000 Hz fare quite well: Aside from occasional bouts of elevated noise, polling is generally stable, and even at 8000 or 4000 Hz, outright missed polls are a rarity. At and below 1000 Hz, however, bouts of elevated noise are common, and 1000 Hz even has the odd missed poll. At the same time, the degree of target deviation is rather low, and thus may be considered negligible. A rather useful feature is the ability to set polling rate separately for wired and wireless use within Glorious Core, although this is currently bugged, as in wireless operation, only up to 4000 Hz can be set for wired. Another bug within the software pertains to lift-off detection. As long as Glorious Core is running, this will always default to the highest (2 mm) setting, even if the lowest one (1 mm) has been set. Without Glorious Core running, it essentially comes down to random chance whether the 1 mm setting is actually applied or not. Hopefully, this will be addressed in a firmware update by Glorious. Lastly, CPI deviation on the Model O 2 Pro 4K/8KHz Edition is a bit higher than I'd want it to be, requiring one to adjust each step manually to attain the target value. That said, Glorious got near-zero deviation in their internal testing, so it is at least possible that the deviation is actually lower than indicated.

Speaking of Glorious Core, in the past year Glorious has been working on lowering its RAM footprint, and with good success. Instead of 300 MB and more, Core now typically occupies around 125 MB, which still isn't ideal but is a major improvement regardless. Furthermore, when exiting Core, no additional processes keep running, which is another plus. Unfortunately, battery readings are still an issue. Since the Model O 2 Pro 4K/8KHz Edition lacks a fuel gauge IC, fully accurate readings cannot be expected anyway, but even non-accurate readings at times fail to show up. In my case, even after five hours of use at 4000 Hz, the indicator still showed 100%, which is impossible. Glorious cites up to 35 hours at 4000 Hz and up to 80 hours at 1000 Hz. Given that doubling polling rate typically roughly halves battery life, I have my doubts regarding the 4000 Hz figure, and based on my experience with the Model D 2 Pro 4K/8KHz Edition, which has the same battery capacity of 380 mAh, I consider around 20 hours at 4000 Hz a more realistic figure. In any case, at just short of 0.2 A, charging isn't exactly fast on the Model O 2 Pro 4K/8KHz Edition, but the charging cable is very flexible, and since wired also has 4000 Hz polling, the experience is a seamless one regardless.

Albeit not without flaws, the Model O 2 Pro 4K/8KHz Edition marks a return to form for Glorious. In fact, if Glorious manages to iron out a few remaining bugs, the Model O 2 Pro 4K/8KHz Edition is a serious contender for releases such as the Razer Viper V2 Pro or LAMZU Atlantis 4K, as the Model O 2 Pro 4K/8KHz Edition enjoys either a feature or price advantage over those competitors. As such, the Model O 2 Pro 4K/8KHz Edition earns our Recommended award.