While the Prime Wireless had its flaws, it proved to be a good mouse nonetheless. By and large, the same applies to the Prime Mini Wireless, though for whatever reason, SteelSeries has managed to make it worse in several aspects.

As the name already subtly suggests, the Prime Mini Wireless is a smaller Prime Wireless. While the latter weighed 80 g, the Mini comes out at 76 g. While this is still sufficiently light, it is merely 4 g less than the larger Prime Wireless, whereas the Prime Mini is 6 g lighter than its wired counterpart. I don't know where that discrepancy comes from, but if I had to take a guess, I would say the different side-button construction accounts for some of the additional weight. Either way, SteelSeries claims 73 g, but that is very clearly not accurate. Accordingly, for those looking for a lighter-weight Prime Wireless, the Prime Mini Wireless is not a good option and should only be considered by those wanting a plain smaller mouse as weight savings are minimal. In terms of build quality at least, the Prime Mini Wireless is still impeccable, as my copy doesn't have any creaking, flexing, or the like and simply feels rock-solid all around.

Fortunately, and unlike the Prime Mini, the Prime Mini Wireless hasn't received any downgrades to its MCU. Accordingly, wireless and sensor performance still are great. There is little to no added delay at the onset of motion, wireless delay sits at just 1 ms, and general tracking is great. There are, however, occasional polling outliers, much like on the Prime Wireless previously. I'm unable to reproduce these consistently, but frankly, they happen infrequently enough to where they are merely an anecdote rather than an issue worth further scrutiny. CPI deviation, on the other hand, is a real issue, and already plagued the Prime Wireless. On the Prime Mini Wireless, the deviation is worse than ever, and since the TrueMove Air is restricted to CPI adjustment in increments of 100, getting certain CPI steps becomes impossible altogether. In particular, 400 and 800 CPI remain but a desire, as CPI adjustment behaves in a non-deterministic fashion. That is, two steps nominally separated by 100 CPI may in fact end up deviating by something like 170 CPI in practice. Furthermore, the TrueMove Air still lacks the ability to adjust LOD, which is a function otherwise native to the PixArt PAW3335, which the TrueMove Air is a variant of. Granted, LOD is low enough as-is, but why not provide the option if it already exists on a sensor level? On that note, I have to wonder why SteelSeries still uses the PAW3335 on their flagship models when the competition has been adopting the superior and more recent PAW3370 for more than a year now. Issues with CPI deviation in particular are rarely found on the 3370, so the benefit would be very obvious.

Another area where the Prime Mini Wireless quite literally is lagging behind is click latency. While SteelSeries does use optical switches on the Prime Mini Wireless, their latency is astoundingly poor. What's more, click latency is significantly worse than on the Prime Wireless, which is truly mind-boggling. Frankly, click latency of this magnitude on an optical switch is simply inexcusable. On a mechanical switch, click latency on button-down is typically introduced when switches need debouncing, but on an optical switch, there is nothing that would need to be debounced aside from preventing slam-clicking, which can be done in a more elegant and latency-neutral fashion, as proven by Razer's optical switch implementations. Accordingly, this is nothing but poor engineering on SteelSeries' part.

To add insult to injury, the main buttons themselves aren't even good. Once again, the left and main buttons aren't consistent at all, and even though pre-travel is lower than on my copy of the Prime Mini, the overall impression continues to be lacking. The right button in particular provides dull and muted feedback to where one could confuse it with a tactical switch. The side buttons, at least, are much better, shining with minimal pre and post-travel, and they don't sound as hollow as the Prime Mini side buttons, albeit still less solid than those of the Prime Wireless. The scroll wheel too fares well, providing very tactile scrolling, albeit in conjunction with high noise levels when scrolling. The feet and charging cable are no different from the Prime Wireless, which is why I have nothing to complain about on that front.

The wireless experience on the Prime Mini Wireless is still a pleasing one since battery life appears to be strong and charging is very fast. One has to wonder, though, why SteelSeries still doesn't make use of the Bluetooth functionality present on the MCU. When the chip already has the ability, why not just use it? In the same vein, I find it questionable that SteelSeries continues to bundle SteelSeries Engine with GG even though GG provides no benefit whatsoever for someone who simply wants to adjust settings on the Prime Mini Wireless and nothing else. Functionally, there is nothing in Engine that would require GG as a prerequisite, so why force people to use GG, which does nothing except use more resources?

All in all, I don't consider the Prime Mini Wireless a bad mouse. On the other hand, SteelSeries does charge $129.99 for it, and at that price point, I would expect click latency to meet today's standards, and a long-standing issue such as CPI deviation to be fixed after two years of this sensor being around. When comparing the Prime Mini Wireless to the competition, it simply doesn't look good for SteelSeries. The Cooler Master MM731, for instance, has a PAW3370, no issues with CPI deviation, optical main button switches yet low click latency, and even weighs substantially less, but only costs $89.99. The only area where the Prime Mini Wireless is better is wireless motion delay, but we're talking about a difference of 1.5 ms, which is hardly worth $40. The Glorious Model D- Wireless is even offered for $79.99 and too comes with a 3370, low click latency, a lower weight, and only slightly higher wireless motion delay. I could go on like this for several paragraphs. The point is that in a market this rich with great and affordable alternatives, the Prime Mini Wireless cannot keep up.