While the X17 had several flaws, it also showed ambition by implementing true 8000 Hz polling and highly granular lift-off distance adjustment owing to a triple-sensor array. While the X20 keeps the LOD sensors, it loses the 8000 Hz polling in favor of wireless functionality. Unfortunately, and contrary to what one may expect, achieving a good wireless implementation turned out to be more difficult than 8000 Hz polling.

Among the greatest strengths of the X17 were the buttons, and the X20 is no different. Being pre-tensioned, the main buttons in particular provide an incredibly satisfying and snappy response. The other buttons are no slouch either, though their placement yet again proves to be less than ideal. First of all, the large sniper button is positioned right above the other side buttons, where it is out of the way yet completely defeating its purpose as a sniper button—that is, a button you'd want to press and hold when precision is called for. Since the sniper button already takes up most of the space, the side buttons are relegated to where the thumb would usually sit. As a result, I accidentally hit the side buttons more than just once during play, and constantly having to be mindful not to hit them proved to be a rather tiresome task. There simply isn't enough room for the thumb, which is why I consider this design ergonomically flawed. The scroll wheel, on the other hand, is much better: Scrolling is noisy, but the steps are nicely separated and provide good tactility, and the ability to horizontally tilt the wheel is quite useful for productivity work in particular. In general, the X20 is built rather well, and the fact that EVGA feels confident in giving a 3-year warranty is no doubt reassuring.

When it comes to sensor and wireless performance, the X20 begins to struggle. PixArt's PAW3335 is used, which is a perfectly fine sensor if implemented well. Unfortunately, this isn't really the case on the X20. First of all, there is significant CPI deviation, which the 3335 is notorious for. A recent firmware update addressed this to some degree, but only for the 800, 1600, and 3200 CPI steps, whereas 400 CPI continues to be way off no matter what. Second, polling stability is poor on the X20. In wired mode, enabling any kind of RGB lighting utterly ruins polling stability. No such thing happens in wireless 2.4 GHz mode, but 500 Hz and 1000 Hz suffer from major instability even without RGB lighting, with 500 Hz being the biggest offender. On the positive side, isolated wireless delay is pretty good at 1–1.5 ms, and the behavior commonly encountered on many 3335 implementations whereby motion delay is greater at the onset of motion is entirely absent. As for click latency, a recent firmware update has improved things, and the X20 now sits around where the X17 did. Lastly, at 125 g, the X20 is heavy to where I noticed hand fatigue the next day after an extended session.

Despite featuring an absolutely massive 900 mAh battery, battery life without illumination sits at no more than 60 hours, and with illumination, just 24 hours can be expected. It stands to reason that the two additional lift-off distance sensors consume a lot of power, likely cutting battery life down by a third or more compared to them not being there. While the LOD sensors do add some utility, sacrificing this much battery life for them surely isn't worth it as the huge battery makes an already heavy mouse even heavier. Frankly, on a mouse this heavy, I'm less worried about the LOD being as low as possible and more about the act of lifting the mouse up and down, which is made all the more strenuous due to the weight. And even though the X20 charges reasonably fast, it still takes quite a while to fully charge it due to the battery being this big. This would be less of an issue if the cable were flexible enough to use the X20 during charging without feeling restricted, but the stiff charging cable makes this a non-option. For those valuing high battery life, the X20 at least comes with Bluetooth.

As for the software, the X20 is compatible with EVGA Unleash, which once again provided a pleasant experience. Easy to install and maintain, with all the important options and even a battery indicator with single-digit precision included, Unleash is appreciably light on resources and doesn't annoy me by spawning more than a single process. Aside from a minor UI bug, Unleash is remarkably stable and mature.

As you can see, the X20 is very much a mixed bag. Now, this wouldn't be too much of a problem if it weren't for one thing: the price. At $119.99, the X20 is similarly priced as many of its competitors without being anywhere near as good. For $99.99, one could make a case for the X20, and sure enough, it is often discounted for even less, but at MSRP, I simply cannot hand out our Recommended award in good faith.

This becomes very apparent when looking at the competition. Priced at $129.99, the ROCCAT Kone Pro Air too has no holes, is way lighter at 73 g, has great build quality and 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 in 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 good enough, and a wireless extender is included. The 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 in the box, but 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 ROCCAT Kain 200 has a shape quite similar to the Prime Wireless, but suffers from significant motion delay and CPI deviation, is somewhat heavy at 105 g, and scores in the button and scroll-wheel department, along with great build quality, for $99.99. For $74.95, the Pulsar Xlite Wireless decimates the X20 in every possible way: performance, weight, click latency, and value. That said, the lack of a traditional bottom plate may be irritating to some. 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.