The Aerox 9 Wireless can be summed up very succinctly: Essentially, SteelSeries took the Aerox 5 Wireless and simply replaced the left side panel with a 12-button grid for MMOs. Once we look below the surface, however, several notable differences come to light, which make the Aerox 9 Wireless an even less compelling offering than the Aerox 5 Wireless.

First of all, much like the Aerox 5 Wireless, the Aerox 9 Wireless suffers from poor battery life. By default, the RGB lighting is configured in such a way that it is dimmed or disabled whenever the mouse is actually moved. With these power-saving features disabled, the Aerox 9 Wireless barely makes it past the 10 hours mark, which is embarrassing. MMO players in particular tend to play for extended periods of time, and on the Aerox 9 Wireless with full RGB lighting, one would have to charge the mouse at least every other day. Granted, charging is reasonably fast, but even with the RGB lighting turned off entirely, the Aerox 9 Wireless might last for 50 hours at most, which is a far cry from SteelSeries' 180 hours claim, which apparently only applies to Bluetooth. What's more, the RGB lighting doesn't even include the most important part of an MMO mouse, namely the side buttons. Especially when playing in the dark, lit side buttons can be useful, but on the Aerox 9 Wireless, the side buttons aren't lit at all. Since the side buttons also lack any other physical features that would make distinguishing between them easier, the Aerox 9 Wireless fails to meet the minimum standard for any MMO mouse. That the side buttons aren't arranged in a straight grid, but rather with an offset doesn't help in this regard, either.

Another notable omission is the lack of a dedicated shift button or any shift functionality altogether. On most MMO mice, one can hit a specified shift button in order to access a secondary set of button maps. The Aerox 9 Wireless has none of that, restricting one to 18 button functions at most. Aside from the 12-button side panel, the Aerox 9 Wireless also has a tilt wheel, which works well and has use beyond MMOs for office work, in particular horizontal scrolling. Compared to the Aerox 5 and Aerox 5 Wireless, the Aerox 9 Wireless uses a different wheel encoder, which is equally tactile but a bit quieter during operation. The side buttons themselves are excellent: Pre and post-travel are surprisingly low, the pressure point even, and stiffness high enough to prevent accidental actuation without feeling overly strenuous. Instead of a membrane pad, proper tactile switches are used for every single side button, which is commendable. The main buttons too are well-suited for MMO play: light yet snappy and firm in actuation, and at a rating of 80 million switches, durability should not be a problem on paper at least. That said, the operating voltage of the main button switches is rather low, which is likely also why SteelSeries opted for a higher debounce time value, in turn resulting in increased click latency. At 6.9 ms in wired mode, click latency isn't exactly great, but on an MMO mouse, durability is more important than the lowest possible latency, so I don't take particular issue with this.

When it comes to performance, the Aerox 9 Wireless is on the same level previously shown by other recent SteelSeries wireless mice. The TrueMove Air sensor once again displays significant CPI deviation, which is doubly worrisome due to CPI adjustment being restricted to increments of 100, effectively preventing one from attaining specific CPI steps in practice altogether. Luckily, CPI accuracy is less of a concern on an MMO mouse, so the Aerox 9 Wireless gets more of a pass here than an FPS-focused mouse. Wireless motion delay yet again sits at just 1 ms, general tracking is fine, and polling stable, aside from some rare moments during which polling breaks down entirely for no apparent reason. Even more curiously, I've been able to measure a minor motion delay of roughly 1 ms even below 6200 CPI, which is where smoothing first applied. On an MMO mouse, motion delay this minor can be forgiven, though. Somehow, lift-off distance is lower than on the Aerox 5 and Aerox 5 Wireless, which, coupled with the lower CPI deviation, points toward the mounting height of the sensor differing from the aforementioned mice.

In general, I do get the impression that the mechanical design of the Aerox 9 Wireless has been put together more hastily than that of the Aerox 5 and Aerox 5 Wireless. While overall build quality is similarly good, there are visible gaps at the front where the side panels and front part of the bottom shell meet. Moreover, the side panels aren't entirely stable by themselves, which is why SteelSeries had to integrate a plastic assembly that acts as a spacer, preventing the left side panel from caving in when pressed. As a result of this measure, the different scroll wheel construction, and more numerous side buttons, the Aerox 9 Wireless ends up weighing 15 g more than the Aerox 5 Wireless despite being the same mouse otherwise. While still light for a wireless MMO mouse at 88 g, a more refined mechanical design would've enabled SteelSeries to use a larger battery at the same weight, which would've been most welcome. Typically, an MMO mouse isn't moved much, so weight is not much of a concern, but battery life is, which is where the Aerox 9 Wireless falls short in. Another curiosity is that all connectors inside the Aerox 9 Wireless have copious amounts of glue on them. It is entirely beyond me what purpose all that glue could serve, and if anything, it only makes it harder to replace parts in case something breaks.

As with other recent SteelSeries releases, SteelSeries GG is the software of choice for the Aerox 9 Wireless. On an MMO mouse, leaving the software up and running is usually the preferred course of action, which is why the significant RAM usage of GG is rather unfortunate. More importantly, GG itself still serves absolutely no purpose for those who simply want to use Engine to configure their mouse, doing nothing aside from wasting RAM. As mentioned, the lack of shift functionality along with the omission of features native to the sensor, such as lift-off distance adjustment, makes using GG an even less appealing experience.

The biggest issue, however, is the price. $150 is a lot of money for any gaming mouse, but for an MMO mouse, it is simply ridiculous. Many people play other games aside from MMOs, and the Aerox 9 Wireless isn't really suited for those. Accordingly, one would have to purchase another mouse on top of the Aerox 9 Wireless, at which point one would be paying upwards of $200 just for mice. While the $10 premium over the Aerox 5 Wireless is reasonable, the $140 the Aerox 5 Wireless retails for is not, and the Aerox 9 Wireless also has its fair share of issues. Simply put, the Aerox 9 Wireless is way overpriced for what it is.