For some reason I can't entirely discern, I have been addicted to collecting little keychain flashlights since the Nitecore Tube made its debut. Since purchasing the first version of that little light, I have since added a Nitecore TIP, a Surefire Sidekick, a Manker LAD, and now this Nitecore TUP to my small collection.That being said, this light in my opinion most directly competes with the Surefire Sidekick at its price point, and so I will draw many of my comparisons from it.First and foremost is size. As pictured, it's about the same length as the Sidekick, which is itself about the size of a key fob. The TUP is also narrower than the Sidekick, but with a significant bit more depth, especially around the reflector. Despite the slightly larger size, it doesn't feel overwhelmingly large or heavy in the pocket.Next is the UX, which I have always had mixed feelings about with regards to Nitecore flashlights, especially the sometimes cumbersome lock mechanism.In this case, the locking has been made much more intuitive; when turning the light off, hold down the power button for a few seconds after the light goes out and it will lock. From there, simply double press-then-hold the power button, and the light will quickly resume at the intensity it was locked at. In my opinion, this far exceeds the quality of the operational experience of Nitecore's other two-button flashlights.The OLED display is also nice, providing feedback on the light's status, battery level, estimated run-time remaining, some of which is even rather smoothly animated. It's a bit flicker-y, but not overly bright, and quickly shuts off when not interacted with.Build quality is mostly good, though lacking in a few areas. The ring for affixing the light to a keychain is quite small, which limits the size of keyring that will fit into it, and overall, it doesn't seem on par with the rest of the light's quality (it's basically a really small keyring kinda shoved into the back of the light), and something closer to the TIP's would be much better.I originally thought my OLED display was scratched, but it was actually a very thin film applied to the display - the panel itself is pristine.Lastly, I have provided a picture of the beam patterns of both the Sidekick (left) and TUP (right). Both lights were on their lowest setting (5 lumens for the Sidekick, 1 lumen for the TUP). In general, the TUP's total internal reflection optic has a narrower, more intense spot than the Sidekick's orange-peel reflector, although it is not without spill.Although both beams actually occupy approximately the same area, the TUP's spill is far less pronounced overall, making it far less evident in the picture. In a side-by-side test, the TUP's beam was more intense at a distance than the Sidekick, despite the TUP being on a slightly lower-intensity setting than the Sidekick.Overall, the TUP marks a great improvement in UX for Nitecore, and it definitely beats the Sidekick; if you're in the market for a light of this size at this price point, you can't go wrong with it.