Security people recommend Signal a lot (e.g. https://medium.com/@thegrugq/signal-intelligence-free-for-al..., Snowden uses it and repeatedly recommended it: https://twitter.com/Snowden/status/661313394906161152, ...). Personally, I use it all the time and it's nice. Most of the initial problems have been sorted out, so I encourage anyone who's had trouble with it before to try it out again.

It has text (one-on-one and groups) and voice calls. Things that could use improvement: group management, switching to a new device. It doesn't have some of the features some people like (stickers and whatnot), but personally I don't care much about those. Video calls would also be nice.