My thoughts as well. If the product is free, who is paying the devs? Who is paying for infra? I'm exclusively on Threema since it's not free, and the yearly external code reviews are stellar. The only thing that bugged me was that it was not open source, which changed by the end of 2020. Multi device coming this year, which was the last thing missing for my use case.

> signal

Amongst many, many other factors, it's a nonprofit foundation, not a commercial company.

Long term, it has backing from people (like the original founders of Whatsapp) who want to see an open solution flourish. Plus people can donate.

Also, both the client and server are open source.

You don't have to pick a messaging app for life.