The update to Android 9 Pie with a new One UI interface is the biggest visual change Samsung has pushed to its phones in years. Alongside all of the requisite improvements you expect with any software update, Samsung's Pie release makes substantial changes to the look and operation of the entire software experience. But naturally, much of Samsung's legacy software is here to stay as well, making sure you'll never forget what kind of phone you're using. This is how it all comes together in Samsung's latest software: One UI and Android 9 Pie. Samsung One UI What I like

Every couple generations, Samsung makes a big step forward in software design and capabilities. I'd argue that Samsung's software got good starting with Android 5.0 Lollipop on the Galaxy S6; but it really only stepped up to being great with Android 7.0 Nougat on the Galaxy S8. One UI with Android 9 Pie is undoubtedly another major step forward. Verizon is offering the Pixel 4a for just $10/mo on new Unlimited lines One UI is effectively a complete redo of Samsung's interface, colors and iconography from top to bottom. Far more than a coat of paint. The software is even further flattened, and puts emphasis on whites and greys with liberal use of soft-radius corners and negative space. In many ways One UI follows Google's Material Design principles — take a look at a Pixel 3 alongside a Note 9 and there are striking similarities in the notification shade, settings, multitasking screen and menus. Visually, this is the best software Samsung has ever made. The consistency of design implementation across the interface and apps is near-perfect, and it feels light and modern both at a glance and with use.

The improvements aren't limited to style; they also have some substance. The biggest change in principles across the entirety of the interface is the move to bring interaction points further down on the screen so you don't have to reach to the top of the phone as often. Throughout the interface and Samsung's own apps, the main interaction points have effectively shifted down to only fill the bottom two-thirds of the screen — the top third, in return, is mostly for viewing rather than touching.

This leads to some awkward blank space at the top of many apps, but when you stop thinking about it and realize the benefits of not having to reach the top of the screen — on increasingly tall phones — it makes a ton of sense. The paradigm of course breaks down when you use third-party apps, but Samsung has done everything it can for its own software to make things a bit more one-handed friendly without having to jump into the dedicated one-handed mode as often. This is also the first Samsung software to incorporate a full dark mode option, available at the tap of a button. It isn't as customizable as what OnePlus offers, nor is it dynamic like Google's, but it's miles ahead of having to apply a system-wide third-party theme as before. The dark mode is actually called "Night Mode" and is ostensibly designed to be used at night to reduce eye strain, but it's completely separate from the blue light filter and can be turned on manually or set to a schedule. And unlike the theme approach, night mode touches every part of the system and Samsung's apps for a complete black-out look. Not everyone is a fan of dark mode, but the contingent of dark mode fans is too big to ignore at this point.

Although conservative, Samsung's first step into the world of gesture-based navigation is successful. It (smartly) chose not to fully implement Google's navigation system, nor did it go its own way with something altogether new and elaborate — the result is a navigation system with copious options that help blend the best of Oreo and Pie. Critically, if you want to keep things exactly as they were you can hold onto three-button navigation (and yes, you can swap the back and recents buttons). But Samsung included Pie's home button left-to-right swipe gesture for quick multitasking, while also retaining the recents button. If you prefer to save some screen real estate, you can replace all three buttons with simple swipe-up gestures in their place. No complicated mix of multiple gestures or different lengths of swipes; just a straightforward replication of what you know from the buttons. The entire interface looks better, is easier to use, and simply integrates Pie's gestures and multitasking. No matter how you get there, the multitasking screen itself looks near-identical to Google's own, with horizontal cards and smartly predicted app suggestions at the bottom of the screen. Some decry the lower information density in this view compared to the old Rolodex-style interface. But this is far more user-friendly and provides quick access to the last three apps you used, plus suggested apps, which is what most people want most of the time. Samsung managed to incorporate gestures and many of Android 9 Pie's native multitasking features cleverly, while retaining the old options for those who update from Oreo — it's the best of both worlds. One UI is filled with lots of little tweaks strewn about its apps, but these have far less impact on the daily experience that's so often dominated by third-party apps people often prefer over Samsung's built-in options. The camera app got some of the biggest user-facing changes, but for the most part all of the apps were simply redesigned to fit the new design language rather than dramatically change their function. But it shows that Samsung is continuing to focus on visual consistency across its apps — even if not everyone uses them. Samsung One UI What's not great