Looks-wise, Skype for Windows Phone is almost identical to the Android and iOS Skype apps. Unfortunately, the video quality isn't as impressive as it is on other platforms, and the app is missing a few features.
Skype is a service that lets you send instant messages and place video and voice calls over the Internet. What started as a desktop app eventually moved to mobile, with Windows Phone getting the app last, in February 2012, just four months after Microsoft's acquisition of Skype for $8.5 billion was finalized in October 2011.
You'll need to sign in to a Skype account to use the app. If you don't already have one, you can sign up from the app, but I don't recommend it, as once you tap "create a Skype account," the full-size sign-up page launches in Internet Explorer, which is a pain to fill out on a smartphone-size screen. This is not the case with the other mobile Skype apps.
If your Skype account is already linked to your Microsoft account, you can sign in with those credentials. However, if you haven't already linked your Skype and Microsoft accounts, you can't do it from the app -- you'll need to download a desktop version of Skype to accomplish that.
It's disappointing that there's no way to sign in with the Microsoft account that you must have set up on your phone in order to have downloaded the app in the first place. It's worth noting you can't link your Skype and Microsoft accounts on any of the mobile apps, either, but I was hoping Microsoft would put a little more thought into the app it built for its own mobile platform.
Instant message, voice calls, and video chat
After you sign in, you see your most recent Skype activity first, including phone calls and chats. On that main screen, you can quickly make a voice call or start a new chat. Unfortunately, you can't easily initiate the most-used feature of Skype: video calling.
Starting a video call is a tedious process that involves swiping over to your contact list, shown in the app as "People," tapping on a person's name, then tapping the video camera button that appears. The app then launches your front-facing camera and shows the other person's video feed full-screen, with your video feed in a smaller window on the right. You can switch the camera or turn off the video altogether, plus you can mute your microphone.
In order to test the video call quality, I used two Windows phones (a Nokia Lumia 925 and HTC 8X) and two Android handsets (Samsung Galaxy Note 2 and Galaxy S4) on the same Wi-Fi network standing in the same location. Video calls between the two Windows phones looked unimpressive and overall fuzzy. Calling from Windows phone to an Android phone gave me slightly sharper video quality, but nowhere near as clear as Skype on Android.
Voice calls performed better, with no significant audio issues, though both video and voice call quality depends on your data or Wi-Fi connection, so your experience may be different.