The Start screen is a bit more sophisticated and more visually appealing in Windows 10 Mobile. Of course, most of the heavy lifting to the Start screen usable occurred in Windows Phone 8.1, such as the introduction of folders.
The changes in Windows 10 Mobile's Start screen are mainly stylistic, such as the ability to put an image behind the tiles. As a result, the live tiles -- long a key strength of Windows Mobile's UI -- feel much more compelling. I only wish that the tiles weren't all so similar, as it can be hard to find the tile whose information you want to glance at or whose app you want to open.
The Action Center -- the pull-down tray of widgets -- in Windows 10 Mobile has become a true center for actions, with access to all sorts of settings, notifications, and applets.
You can finally respond to a notification from the notification itself, not launch its app first. These UI adjustments combine to make Windows 10 Mobile feel like an adult platform, finally comfortable in its own skin.
But the biggest advancements in Windows 10 Mobile relate to security and apps.
Windows 10 Mobile finally lets users enable device encryption for local contents; Windows Phone 8 supported encryption only if enabled by IT through an Exchange or mobile management server.
The user-enabled encryption key in Windows 10 Mobile is also stored locally, so Microsoft or your company can't give the FBI the key to access your device, as they can with the server-enabled encryption.
On the app front, the biggest advancement is that the real Office suite, not that abomination known as Office Mobile, is now available for Windows smartphones.
That brings Windows smartphones up to parity with iPhones and Android smartphones for office productivity -- and nearly as capable as the desktop Windows and Mac versions. Microsoft's mobile communications tools, such as Outlook and Skype for Business, are also available for Windows 10 Mobile, where they are basically at parity with their iOS and Android equivalents, though not as capable as their desktop versions.
What's not to like about Windows 10 Mobile
Although Windows 10 Mobile is now a comfortably useful platform, it has nowhere the rich functionality of iOS or Android, so the more you use a smartphone as a portable computer, the less you'll like Windows 10 Mobile. It's still aimed at basic usage.
For example, the list of business-class apps available for Windows 10 Mobile remains very short, though it boasts Adobe Acrobat Reader, Cisco AnyConnect, Cisco WebEx Meetings, Concur, Evernote, GoToMeeting, Slack (in beta), TripIt, and Amtrak and a few airline apps. As you can see, they're not much. Worse, many of these apps crow about being the "new" Windows 8 or 8.1 versions at the Microsoft Store. Ahem.
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