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If you've used a Windows Phone device before, then the Nokia Lumia 635 will feel familiar to you.
You get the same rigid two-homescreen layout, with the first dedicated to widget-like Live Tiles that provide you with key information at a glance (such as freshly taken photos, or news headlines), and the second showing you a simple list of installed applications.
Familiar, then. But not identical.
For while Nokia hasn't modified Microsoft's OS at all (beyond a few additional settings and stock apps), when it launched this was one of only two smartphones to run Windows Phone 8.1. It's a subtle update from WP 8, but it does bring some notable additions.
As mentioned in the previous section, the most noteworthy addition here is Action Centre, which is the name Microsoft has given to Windows Phone 8.1's long-awaited notification menu.
Now, when you drag down from the top of the screen from within any app, an overlay will drop down detailing your latest unread notifications. Emails, SMS messages, social network posts, app updates, downloads - anything you need to know about will be in here.
Tapping each notification will jump you to the appropriate app, while a swipe will dismiss it from view.
Notifications aren't the only thing you'll find in Microsoft's new Action Centre. You also get some handy shortcuts for commonly-used functions. By default this includes Wi-Fi, Bluetooth, and screen brightness toggles, as well as a camera shortcut (handy given the lack of a physical camera button).
These can be swapped out and customised in the settings menu, so you can add a rotation lock toggle, a flight mode shortcut, or a range of other functions.
Talking of the settings menu, Action Centre also provides a shortcut to this vital hub. Indeed, it felt like I spent a little too much time in this settings menu, and it was slightly overloaded with options that were difficult to sift through and differentiate.
Of course, such tweaking shouldn't be necessary for the average casual user, and Windows Phone has never been more usable outside than it is here.
A large part of that is down to Action Centre, but there's also a neat lock screen that helps. Once again you have to dive into that murky settings menu to get it running to its full potential, but once you do you can set the background image to reflect the weather or your Facebook account, to name but two options.
You can also choose an app from which to show a detailed status, such as your latest email, and to show artist information when playing music.
Also new to Windows Phone 8.1 is an improved keyboard. It still looks much like the stock (and non-swappable) Windows Phone keyboard of old, but it now comes with the addition of Word Flow.
If you've ever used Swype or SwiftKey Flow on Android, you'll know what this means. You can type out words by sliding your thumb between letters, with spaces entered when you remove your finger from the screen.
It can be extremely quick to type out words in this way, once you grow accustomed to it, and it's more reliable when trying to type one handed whilst walking along. It's a welcome addition, though with Apple unexpectedly joining Android in relenting to demands for third party keyboard support in iOS 8, it's in danger of looking like a token gesture on Microsoft's part.
Since launching, the Nokia Lumia 635 has been updated to Lumia Denim, which lets you make use of Cortana, Microsoft's virtual assistant, which can answer your questions, launch apps and carry out other tasks, just like Google Now or Siri.
Among other minor tweaks and additions Lumia Denim also added Live Folders, so you can group apps together on the home screen.
General navigation through Windows Phone 8.1's menus on the Nokia Lumia 635 was predictably smooth. There were no stutters at all when flitting between the home screens and scrolling down through my Live Tiles, which is what I've come to expect from Nokia and Microsoft's joint efforts.
Where I did notice performance issues was in more intensive tasks, such as when installing or updating multiple apps, which caused significant (though temporary) freeze-ups.
Jumping into the camera, too, takes longer than I would like.
You might initially be surprised at this when you consider the Lumia 635's hardware. While it only runs on a relatively modest 1.2GHz processor, it is a quad-core Snapdragon 400 unit.
This somewhat sluggish performance was reflected in my benchmark tests. An average WP Bench score of 255.45 is significantly slower than that of the Nokia Lumia 1320 at 312.22.
The Lumia 1320 runs on a dual-core variant of the same Snapdragon 400 chip - albeit one that's clocked 500MHz faster, suggesting that the Windows Phone OS perhaps continues to be optimised for raw clock speed over multi-core cleverness.
Of course, a more likely culprit in all of these performance issues is the Nokia Lumia 635's 512MB of RAM, which is half that of the aforementioned Lumia 1320.
It has an effect on game playing too. Taking Asphalt 8 for spin, while general performance was okay, there were periodic stutters to both the frame rate and the soundtrack - a sure sign that the Lumia 635 is straining against memory limitations.
Of course, when placed against Nokia's older budget phones like the Lumia 520 and the Lumia 620, the Nokia Lumia 635 comes out on top thanks to its stronger processor.
When viewed in this entry-level context, it's a decent little runner. Just don't expect a premium, completely uncompromised Windows Phone 8.1 experience and bear in mind that there are newer yet still quite affordable Lumia's now, such as the Microsoft Lumia 640, which has 1GB of RAM.
