I have been using Lync and its predecessors for quite some time and I love the platform and all the things it allows me to do on my PC and Mac.
That said, until now, the Mobile App was more or less a worthless joke. Only IM was possible, the audio resulted in some weird callback function and video was a no-show.
In comes Lync Mobile 2013 (which requires that your Lync infrastructure runs 2013).
First of all, installing and configuring is easy if you have Autodiscover enabled. Just put in your SIP adress and domain login credentials and you are ready to go:
Click through some configuration settings and decide if you want to do audio/video calls over WiFi only or also your carrier data connection. All set, now just...
... put in your phone number if you want to use your mobile connection as a backup for VoIP calls (this is basically just forwarding the calls to your mobile phone if Lync Mobile is off).
The app does not only give you the necessary functionality (Audio and Video Calls) but also is much faster than its predecessor. Signing-In and Out is instantanous - which makes the App much more useful, if you are on the road and just want to quickly check what is going on.
Video Conferencing works just fine, perfect quality, even if your WiFi connection is not the best or you don't have WiFi at all.
Altogether I have to say that Lync Mobile 2013 is a great App that just works. It will increase the deployment of Lync and will make your life much easier if you are already on Lync and needed a decent mobile App.
(I reccomended other mobile Apps for Lync before e.g. Xavy or idialog because these did allow for Audio / Video already for years - now, Lync Mobile 2013 does everything these Apps do but also gives you a great designed App that looks and feels like Lync)