SimpleX is awesome. I've been using it since mid March and the big issue has been persuading people I know to use it. Calls sometimes get a bit laggy and sometimes take a little long to connect. If you need calls to show up/ ring on your phone you have to set the notifications to instantly which means you're not on the highest level of privacy. It's still, I believe, way more private than other messaging apps that people use.
#SimpleX