I personally prefer Telegram. It's voice call quality (as well as everything else it offers) feels perfect (your mileage may vary - obviously this depends on yo

I personally prefer Telegram. It's voice call quality (as well as everything else it offers) feels perfect (your mileage may vary - obviously this depends on your location, your ISP etc) and the bandwidth consumption is shockingly humble. It can also let you send voice messages and video messages easily. Video calling is not there, however - it's a feature planned to be shipped later this year.