Hi,
I use Viber on Android regularly. No issues, in recent times.
While I'm not a fan of the stickers, I find the service is generally good.
In particular, I like that I can forward something to multiple people a little easier then on What's App, given the later has restrictions on how many people you can forward something to etc.
A friend who works in tech, told me years ago, that Viber was a better system for calls, than What's App, but for the life of me, I can't recall why.