Best app for voice calls over patchy Wi-Fi

What are the best aspects of this product?

Me and people in my company use Viber mostly in cases when we want to call my contacts in India and Canada. In my opinion it is one of the best best voice calling applications I've tried so far and it works really well even if the internet connection is not that strong (which is often true in my case). Plus, the stickers and emoticons are very funny and attractive for chat users so it's an additional benefit.

What aspects are problematic or could work better?

Incoming calls do not ring outside the app and because of that I miss the calls coming in. Therefore, my contacts need to inform me through text or Whatsapp that they are going to call me on Viber. However, the voice quality over poor internet is much better compared to Skype and Whatsapp, though I think Whatsapp is more easy to use. I think the incoming call notification issue is only on iOS phones as Android users do not seem to be affected by this problem.

Are you a current user of this product?

Yes