Calling the launch of the MM731 "rocky" would be the understatement of the century. While some of the issues were build-related, they rarely exceeded usual first-batch problems from what I can tell. The real issue concerned motion delay, both in wired and, in particular, wireless mode. At first, total motion delay was well over 20 ms, then got lowered to about 6 ms, and through continuous updates over the last few months, has finally reached a decent enough state. While I appreciate Cooler Master spending time and resources to address these issues, I would've much preferred it happening before the release. You only launch once, and hopefully, the MM731 is a lesson learned for Cooler Master.

With that out of the way, let us tend to the most pressing question first: Has the MM731 been fixed? As always, this will depend on what one considers "fixed." In my testing, I can measure a motion delay of roughly 1 ms in wired mode and a motion delay of roughly 2–2.5 ms in wireless (2.4 GHz) mode. These numbers definitely aren't top-tier, but they're certainly not bottom-tier, either. Compared to such a competitor as the Pulsar Xlite Wireless (1 ms delay), the MM731 is behind, but for the vast majority of users, the MM731 is likely responsive enough. In fact, I doubt hardly anyone would be able to tell the difference in a blind test; that is, unless told of it beforehand. Furthermore, general performance is more than serviceable: CPI deviation is decently low, polling stable across the board, and there is virtually no onset motion delay, which plagues a fair few wireless implementations. The only other issue I was able to identify consists of periodic outliers showing up in tracking, which seem to introduce some minor variance. However, this is mostly academical and typically something beyond the limits of human perception. To sum it up, unless one intends to use the MM731 for tournament-level competitive play only, its performance likely won't be a limiting factor.

Another issue the MM731 initially suffered from was slam-clicking. Since the MM731 is using optical switches, there is no need for debouncing, but said lack of debouncing will result in clicks unintentionally registering if the mouse is slammed (or just gently placed) onto the mousepad. Since merely repositioning the mouse can be enough to trigger a click, a fix was in order, which Cooler Master ultimately delivered. Said fix is more of a band-aid, however, as it simply adds several milliseconds worth of debouncing. That said, a recent firmware update has given the user control over how much debounce is supposed to be added, ranging from 1 to 6 ms. At the lowest setting, click latency is appreciably low, but slam-clicking still occurs, but this ceases to be the case at the 2 ms setting, which therefore is the preferred choice. While both Razer and ROCCAT have shown that given properly engineered firmware, resorting to this type of debouncing is not necessary at all, Cooler Master's approach is the second-best way of doing things, and certainly preferable over what SteelSeries did with their Prime series, where latency is both high and non-configurable.

When it comes to the button implementation of the optical switches in general, Cooler Master has done well. I've had two copies in total on my desk, and the left and right main buttons were mostly uniform on both, which is something optical switches tend to struggle with. The right click feels a bit duller than the left one, and the shell imparts a certain degree of hollowness to them, but as a whole, the clicks are quite pleasing. In particular, the shell design is noteworthy, as despite being visually separate from the shell, the buttons sit very firmly with minimal horizontal play, and neither touches the other when both are pressed at the same time. Likewise, the side buttons are very good as well, providing a pleasant button response and decently low pre-travel. Lastly, the scroll wheel is excellent: Noise levels are well under control, and scrolling is highly controlled, with clearly discernible steps and a matching tactile feel to boot. I also have nothing to complain about when it comes to the feet, and for those struggling with grip, Cooler Master included a set of grip tape covering the main buttons and sides.

In fact, when it comes to its build, the MM731 manages to impress. At 59 g and a medium to small size, the MM731 is exceptionally light, yet does without any externally visible holes. Shell rigidity doesn't suffer either, as I couldn't get either of my samples to creak, flex, or actuate their side buttons by squeezing. I've always been of the opinion that given smart engineering, holes as a weight-reduction measure are largely superfluous, and the MM731 is a testament to that belief. Another peculiarity setting the MM731 apart from others is the sensor position. Relative to one's thumb, the sensor is shifted forward, effectively as far as the design allows. While this may feel alien at first, it does provide the benefit of a wider wrist motion arc, which is especially worthwhile for those exclusively using their wrist for aiming. In any case, after getting used to it, it at the very least is not inherently detrimental.

As far as the wireless experience as a whole goes, Cooler Master also has done well. First of all, Bluetooth is on board, which is handy when traveling, or whenever battery life is paramount. Despite the 59 g weight, a 500 mAh battery found its way into the MM731, providing battery life north of 70 hours without illumination. Charging is made hassle-free by the USB Type-C connector and highly flexible cable allowing one to use the mouse during charging with barely any restrictions, even though the charging itself isn't particularly fast. In addition to that, a wireless extender is included, which I consider an essential addition these days, and the dongle can be conveniently stored directly on the mouse.

Speaking of illumination, RGB is kept at a minimum on the MM731 in the interest of both weight and battery life. The little RGB there is has been done tastefully and can be configured through Cooler Master MasterPlus+. While I didn't face any issues with the software itself, resource usage is absolutely massive. As long as the software is open, the RAM footprint kept fluctuating anywhere between 300 to 500 MB, which is a lot. After exiting the software, not many processes keep running, which is a plus, but the RAM usage while the software is running is just too high for my taste.

Alright, what's the verdict then? If one can deal with the fact that the MM731 merely performs very well instead of excellent, one gets a genuinely good mouse that does a lot of things right and is priced appropriately at $89.99. Right now, there are more right-handed ergonomic wireless mice to choose from than ever before. While the MM731 is neither the best nor the most affordable of them, it combines several traits that are either not present at all or not done as well on its many competitors. Accordingly, it is worth more than just a look and rightfully earns our Recommended award. In fact, had the MM731 released in its current state, it may even have gotten an Editor's Choice. On that note, I do hope the MM731 gets the recognition it deserves at last, and that we'll get to see more of this design in the future.

As mentioned, anyone in the market for a right-handed ergonomic wireless mouse is spoiled for choice these days. Priced at $129.99, the ROCCAT Kone Pro Air too has no holes, too is very light at 73 g, has similarly great build quality and great performance, but lacks a wireless extender and suffers from botched polling with RGB turned on. The Razer DeathAdder V2 Pro is also priced at $129.99, weighs a bit more at 87 g, and its main buttons can be hit or miss, but the optical switches afford outstandingly low latency, sensor performance is stellar, polling stable, wireless delay still good, and a wireless extender is included. At $129.99, the SteelSeries Prime Wireless too comes without holes, impresses with its general build and lightweight design, great performance, and has a wireless extender included, but suffers from inconsistent main buttons and lackluster click latency. The $119.99 ASUS ROG Gladius III Wireless weighs 89 g, allows for using either mechanical or optical main button switches, both of which shine with incredibly low latency, has excellent sensor and wireless performance provided the latest firmware is applied, and a wireless extender can be found in the box, though it is brought down by Armoury Crate, which may only please masochists. The much smaller ASUS ROG Keris Wireless lacks a wireless extender, but too has hot-swappable main button switches, great performance, an appreciably low weight at 79 g, very low click latency, and very nice buttons and feet, but again comes with the non-negotiable Armoury Crate burden, for $99.99. The $109.99 Corsair Sabre RGB Pro Wireless also lacks a wireless extender, but scores with incredibly low click latency, great sensor performance, fairly low weight for its size, but too is brought down by the behemoth that is Corsair iCUE. For $74.95, the Pulsar Xlite Wireless has excellent performance, low click latency, a wireless extender included, and weighs 59 g, but the lack of a bottom plate may not be to everyone's liking. The $79.99 Glorious Model D Wireless does have a bottom plate and weighs a bit more than the Xlite Wireless, but is very similar otherwise. Lastly, the Dream Machines DM6 Holey Duo is the budget option, even featuring a wireless extender at a price point of $49.99, weighs 79 g, but suffers from very high click latency, some motion delay, massive CPI deviation, and a coating that attracts finger marks almost magnetically.