Interestingly, Google has none of its apps -- even Gmail, Google Maps, or Google Search -- available for Windows Mobile. If you use Google services, you won't want Windows 10 Mobile.
If you use a Mac, you no longer have an app available to sync files such as music to your Windows phone; Microsoft discontinued that Mac app with Windows 10 Mobile. There's no simple way to load your Windows phone with contents from iTunes; it's evermore difficult than doing so from Android. (However, you can connect Windows 10 Mobile to your Apple iCloud email, calendars, and contacts.)
By contrast, you get the same clients and connections to Microsoft's various services as you do on a Windows 10 PC. Clearly, Windows 10 Mobile assumes -- nay, requires -- you be a Windows PC user who relies mainly on Microsoft's own ecosystem.
The basic installed apps like Alarms & Clock, Outlook Calendar, Outlook Mail, and People are serviceable, but nothing to write home about. They're nearly at parity with Google's default apps on Android, but not as capable as Samsung's, and nowhere close to Apple's.
Windows 10 Mobile also has a lot of junkware, and not only from the carrier. Microsoft has a lot of filler apps pre-installed in Windows 10 Mobile, including Contact Support, Device Help, Food and Drink, Get Started, Help+Tips, Lumia Help+Tips, Lumia Moments, Lumia Selfie, Lumia Storyteller, Money, Movies & TV, Sports, and Storage (which really should be in Settings).
Clearly, the folks that use to clog up Settings with stuff are now developing the help and information apps that litter Windows Mobile. I'm not even counting low-value apps like News, FM Radio (which should be part of Groove Music), Health & Fitness, Podcasts, Skype Video, and Voice Recorder.
From a UI perspective, Windows Mobile's scrollable tiles continue to be a weakness the more apps you have. iOS and Android use pages to organize apps, in addition to folders, and those pages are an easier way to navigate your phone when you have lots of apps installed. Windows Mobile needs a similar feature -- putting everything in one very long scrollable window is very tiresome to navigate.
The tiles are great, though, when you have only a few apps installed -- which is probably the case for most users.
Finally, although I could get AnyConnect to the corporate VPN, I could not get Windows Mobile's Edge browser to successful load our content management system, though the CMS works fine over AnyConnect on iOS, Android, Windows, and OS X. Our CMS does not support Internet Explorer, due to its many nonstandard attributes, but it runs on Edge on the desktop.
It's unclear if this issue is related to AnyConnect or Edge, but with Chrome and Firefox not available for Windows Mobile, I can't tell what the issue is. It's a reminder once again that Windows Mobile doesn't have the platform or application maturity of the other operating systems.
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