In one way or another, all mouse releases from DELUX so far have been a variant of the same ambidextrous shape, which in turn had been closely modeled after the Razer Viper. While DELUX continues to take inspiration from Razer, this time the DeathAdder V3 Pro is the muse. Some minor differences exist between the DeathAdder V3 Pro and M900 Pro, but by and large, their shapes are virtually interchangeable. Moreover, their weight is also essentially the same, with the M900 Pro being only marginally heavier at 64 g. Much like the DeathAdder V3 Pro, the M900 Pro does not resort to holes in the shell or an open-bottom design to achieve this weight, and the battery capacity is a bit larger too at 400 mAh. In terms of build quality, the M900 Pro can't quite keep up with the DeathAdder V3 Pro, however. On my sample, creaking is easily noticeable when applying lateral pressure, though at least not to where it would become annoying during gaming. In addition, the main buttons move around, resulting in a rattle when shaking. I've found the degree of lateral button movement to be lowest when the screws on the bottom are tightened as much as possible, but some degree of button movement will always be present. Thankfully, the side buttons cannot be actuated by pressing below them at least.

For $59.99, the M900 Pro comes with an impressive assortment of switches. For the main buttons, Huano switches (blue transparent shell, pink plunger) are used, which provide a snappy and firm button response, diluted only by the moderate pre-travel. Proper full-size switches also see use for the side buttons, where Huano switches with a white plunger are employed. Pre and post-travel are moderate, and the actuation point isn't entirely even on the back button, leading to somewhat mushy actuation. Compared to the DeathAdder V3 Pro, the side buttons are also smaller and consequently sit higher, making it more difficult to actuate them by rolling one's thumb across. The scroll wheel encoder is from Huano as well, and while noise levels on this one aren't too high, tactility is lacking, as the individual steps aren't particularly well-defined. The feet are the usual white-dyed PTFE fare and are neither particularly good nor particularly bad.

The M900 Pro comes with PixArt's PAW3395 along with a Beken BK3633 MCU, which is mostly known under the CX52850 moniker. Up to 8000 Hz wireless polling is present, despite the dongle being of the usual smaller size. While the M900 Pro indeed identifies as a USB high-speed device in wireless operation, and thus may be counted as delivering true 8000 Hz polling, performance is disappointing nonetheless. The first issue is related to polling stability, or rather the lack thereof. In wireless operation in particular, there is only a single polling rate not suffering from frequent off-period polls, and that is 8000 Hz. All the others are far from stable, lowering consistency in the process. Second, motion delay falls short of the competition. At 1000 Hz, the M900 Pro trails the Logitech G403 (control subject) by roughly 0.5 ms without MotionSync, which is good actually, but increasing polling rate does not change that. Hence, the only benefit afforded by higher polling rates is improved tracking smoothness, though given the corresponding increase in power consumption and thus lower battery life, this is hardly a good trade. In fact, due to what may be presumed to be a larger buffer to reduce the number of missed polls, 8000 Hz actually increases motion delay compared to lower rates. Third, and arguably most important, is the lackluster showing in regard to click latency. Click latency is more or less the same across all polling rates, and provided the 2 or 4 ms debounce time settings are selected, hovers around 6 ms. What's worse, standard deviation is markedly high, which is why consistency is poor as well. Typically, USB high-speed mice exhibit far lower standard deviation compared to regular USB full-speed ones, but on the M900 Pro, this is not the case, for whatever reason. Lastly, on top of adding motion delay, MotionSync is also less effective at tightening SPI timing on the M900 Pro than it should be. The only positive thing to note is CPI deviation being virtually nonexistent.

DELUX cites up to 65 hours of battery life, presumably at 1000 Hz. At 8000 Hz, roughly 15 hours may be expected, but verifying these figures is complicated by the fact that the battery life indicator provides little help in this regard. Even after several hours of usage at 8000 Hz, it did not budge one bit, so I can't even tell whether it works at all. Charging speed at least is on a reasonable level, and the charging cable is decently flexible, too. Of course, the more convenient way of charging is using the included docking station, which, unlike that of Razer releases such as the Viper Ultimate, charges the M900 Pro at the same speed as when using the cable. Even RGB lighting is present on the dock, and can be cycled through a button on the bottom, though unfortunately, the ability to display the current charge level through the RGB lighting is absent. As for the software, I have nothing to complain here—all the important settings are there, resource usage is low, and I haven't encountered any bugs, critical or otherwise. In short: perfect.

Overall, and despite the criticism, the M900 Pro is not a bad mouse. Rather, the issue is that it simply falls short of the competition, especially in the performance department, even when compared against releases in its own price bracket. The inclusion of 8000 Hz is little more than a gimmick, as both motion delay and click latency rank below some of the better 1000 Hz mice, so by all accounts, this is just a regular 1000 Hz mouse in terms of how it performs. On the other hand, for the $59.99 it is priced at in DELUX's own Amazon store, the M900 Pro does provide good value, as the inclusion of a docking station is rarely seen in this price bracket. As such, the M900 Pro is primarily worth a look for those who'd really want a DeathAdder V3 Pro for a third of the price, and can live with some compromises otherwise.