The Lumia 520, just like all Nokia handsets of late, runs on the Windows Phone 8 operating system. Microsoft's phone OS is meant to retain its general look across different devices, but manufacturers are encouraged to build new features on top of it to compete with one another. The Finns are especially inclined to do so since they are the only ones to have WP as their only plaform and as a result have delivered a lot of extras with the Lumia 520.
Before we move on to them, though, here's the Windows Phone 8 user interface on video.
You unlock the Lumia 520 with the familiar swipe up gesture. You can also press and hold the camera shutter key to unlock the phone and jump straight to the camera.
Microsoft has added a lot of flexibility and functionality to the lockscreen - the Live Apps service allows apps to add notifications and images on the lockscreen. You can set one app to display big notifications ("detailed status") and up to five more apps get to show more limited info ("quick status").
The lockscreen wallpaper can also be controlled by apps - one of the installed apps can be set to choose the image (e.g. Bing's beautiful background images or photos from your Facebook account) or you can let the music player change the lockscreen image to the album art of the currently playing track.
The Modern UI is composed of vertical grid of Live tiles, which can be reordered the way you like. Almost anything can be pinned to the homescreen - apps, contacts, web pages and more.
When you tap and hold on a tile, you'll get additional resize button to the unpin one. You can opt between quarter, normal and double size. If you select the smallest one though, the tile will be just a static icon (as is in the regular menu).
To be honest, the process of resizing live tiles could've been better. In order to switch from big to normal and then small you have to hit the same toggle - it would've made more sense if there were separate ones to make a tile bigger and smaller or resize tiles by dragging like in Android.
Most Live tiles display relevant info such as the current date, pending calendar events, missed calls, unread emails and more (third party apps do it too). The Marketplace tile, for example, displays the number of updates available, while the Pictures tile is essentially a slideshow of your photos. It's nice to have all that info always available at a glance. You can look at them as homescreen widgets of sorts, but that's oversimplifying it.
WP8 can do multitasking - well, not true multitasking, but an iOS-inspired approach instead. Apps not in the foreground are suspended, but the OS has ways to take over and carry out the task for them (e.g. continue playing music). But just like iOS, if an app needs to run in the background (navigation clients, messengers, etc.) it can. The WP offers both kinds of multi-tasking and it's up to developers to choose how their apps operate.
In terms of functionality, nothing has changed since WP7.5 - to switch between apps you press and hold the Back key. You'll get thumbnail snapshots of the apps, ordered chronologically left to right.
You can scroll the list horizontally to select an app and a tap will bring you back to your running or suspended app. You can't "kill" any of those apps from here - to exit one you must bring it to front and use the Back key to close it.
Using the Back key for closing apps has its flaws. If you start frantically hitting the back key, sooner or later you will get to a browser window. And this won't close before it goes all the way back to the first loaded page. Anyway, it seems it's best to let the OS manage the apps and not worry about closing apps manually.
Opening the settings menu displays two sets of options: like on the start screen, you can swipe between System and Applications. System covers all the settings you can think of like sounds, color theme, Wi-Fi, Bluetooth, Accounts, etc. The Application settings let you configure each app you have on the device.
We would've liked to see some kind of quick toggles in Windows Phone 8 to spare you the need to go all the way to the settings menu to enable Wi-Fi, Bluetooth, GPS and the likes. For example, changing the brightness setting requires you to go to the settings menu and scroll all the way down - it's basically a head-banging operation involving multiple swipes and taps.
Another feature we feel is missing on the Lumia 520 is a place where you can see all of your notifications from various apps. Live tiles manage to show notifications from each app to some extent, but they don't really have enough room for things like e-mail subject and such, while Android and iOS notification areas do. Microsoft has expressed that it's working on just such a feature and that we should see it in a future update to WP 8 but time has gone past and we've seen nothing of the sort.
Windows Phone 8 also can be controlled through voice only - you can dictate or have the phone read text out, you can initiate searches and so on. Other OSes are doing it too - Android's got Google Now, Apple has Siri and there are a number of third party "virtual voice assistants" available. The Windows assistant though is still far behind the competition.
One of the new features brought by WP8 is the Kids Corner. You can select the apps and the types of media content that goes in and password-protect it, so you can safely share your smartphone with your kids without worrying that they will mess up your settings or access inappropriate content. When activated, the Kids corner is accessible by swiping left of the lockscreen. If you've secured it, your kids won't be able to return to your standard lock and home screen without the password.
Microsoft is trying to appeal to business users too - a company can create its own Hub where employees can find news, calendars and other info to help them with their work. Companies can also create their own apps that only employees can install.
The Nokia Lumia 520 boasts the same chipset as the other affordable WP8 smartphones - a 1.0 GHz dual-core Krait processor paired with an Adreno 305 GPU and 512 MB of RAM. That's close to what the WP8 flagships have (and notably better than competing lower mid-range Androids), which coupled with the relatively light OS adds up to nicely smooth performance.
Higher is better