While a bit smaller, the M800 Pro (3395) essentially is a Razer Viper in both look and feel, except for the price tag: At $49.99, the M800 Pro is substantially more affordable than the $149.99 Razer Viper V2 Pro. Unfortunately, when it comes to performance and quality, one has to make a couple of compromises too many for the M800 Pro to be worth a recommendation.

The main issue is performance. On the M800 Pro, PixArt's latest PAW3395 sensor is paired with a rather obscure MCU from XC Tech. Unlike the vast majority of other wireless mice, the M800 Pro behaves completely different between wired and wireless (2.4 GHz) operation. First of all, wired mode suffers from increased speed-related accuracy variance, or "acceleration" in layman's terms, whereas wireless does not. Furthermore, motion delay continually increases when moving from a standstill, approaching 16 ms towards the end of a motion, therefore resulting in a severely delayed feel, which, coupled with the acceleration, renders wired mode essentially unusable. Granted, charging is reasonably quick on the M800 Pro, and the charging cable is flexible enough to not feel restrictive when charging, but due to the highly inconsistent and delayed tracking, even the little time not spent in wireless operation is a terrible experience. Polling at least is stable across the board in wired mode, which can't be said of wireless mode, as any polling rates below 1000 Hz exhibit at least intermittent instability. In addition, wireless motion delay is around 4 ms on the M800 Pro, though this varies greatly, as the M800 Pro suffers from what I like to call "shift" behavior, whereby at some random point throughout the motion, motion delay will increase by at least one interval. Accordingly, motion delay may be 2 ms initially, then increases to 3 ms, then to 5 ms, and potentially even higher. There is no consistency to this, either, further contributing to the mouse feeling terrible in use.

The lack of consistency applies to click latency, too. When looking purely at the average, the M800 Pro doesn't do poorly at all: When using the lowest debounce time (0/2 ms), 4.0 ms are averaged, which is perfectly fine. However, standard deviation is around 1 ms, which is several times higher than on comparable 1000 Hz wireless mice, which typically muster a standard deviation of less than half. The above average variance directly translates to above average inconsistency, as the first click may be delayed by 2.1 ms, whereas the one after may be delayed by 6.3 ms, only to be succeeded by a 3.5 ms click. Add in the fact that there appears to be some degree of idle delay adding roughly 2 ms on average when not having clicked for a couple of seconds and all consistency goes right out of the window.

Of course, one could argue that it's not entirely about performance, and other parts of the mouse may make up for technical shortcomings. Unfortunately, that isn't really the case. At 71 g, the M800 Pro is decently light for a wireless mouse with a 500 mAh battery and no holes, though considering the lack of RGB lighting, going a bit lighter could be expected. During disassembly, I also couldn't help but notice the presence of an auxiliary PCB carrying an LED for scroll wheel illumination, considering this LED cannot be configured at all, and is only in use when switching on Bluetooth, as the blinking indicates that the device is ready for pairing. Given that there is another small LED at the front of the mouse to indicate charging, the scroll wheel PCB thus could have easily been omitted and a couple of grams been shaved off. Build quality is spotty on my sample: When shaking the mouse, a major rattle comes from the main buttons, which is odd in that the button pieces themselves aren't loose, and an additional rattle from some other indeterminable location is present as well. Applying lateral pressure produces some creaking but no flexing, and while actuating the side buttons by pressing below them is possible, doing so requires excessive force.

For the main buttons, DELUX has opted for Huano switches with a transparent blue shell and pink plunger, which is the same (albeit non-binned) model utilized in recent LAMZU releases. While their actuation is firm and quite pleasing, there is some pre and moderate post-travel, somewhat diluting the otherwise present snappiness of the switches. Instead of full-sized mechanical switches, a set of tactile switches is used for the side buttons, which suffer from significant pre-travel, and due to a less than ideal button design, they can be pressed in quite a bit past the actuation point, too. Actuation is even across their entirety at least, though the hollow yet notably loud feedback isn't exactly pleasant. The scroll wheel encoder comes from Huano, which is a rather unusual choice, and admittedly, I'm not entirely convinced by this one. Scrolling up in particular is noisy, the individual steps aren't particularly pronounced, resulting in merely decent tactility, and the overall impression isn't one of high quality. The same can be said of the feet, which are regular black-dyed PTFE feet, and whose glide is at most decent. A replacement set is included at least.

The software has all the relevant options, and resource usage is pleasantly low, but the battery charge indicator is far from reliable and accurate, so at best one can get a rough idea of when charging may be needed, but little more. In my case, the indicator still stood at 100% even after hours upon hours of use, so gauging anything is simply not possible for me. DELUX cites 70 or 80 hours depending on where one looks, which are plausible numbers given the battery capacity, but ultimately, I have no way of confirming or denying them. Whatever battery life may be, it could definitely be higher if the sleep mode timer could be lowered further, as for whatever reason, the lowest possible value is 3 minutes, which is way too long still. Bluetooth may net more usage in any case, though how much is anyone's guess.

Overall, the DELUX M800 Pro suffers from too many issues to be worth considering, even for the $49.99 it retails for on Mechkeys.com. Both the Darmoshark M3 and VGN Dragonfly F1 Pro Max go for similar money, yet pulverize the M800 Pro (3395) on every conceivable level. Accordingly, I'd steer clear of this one.