The privacy is nice and it's been simple and easy to use.
I hope they stick around. Everyone likes to bash more privacy oriented companies if they aren't absolutely 100% perfect in every single way, but IMO perfect is the enemy of good and Signal has been very good.
The hardest part has been convincing people to use it, and if I have to get people to jump to another one it'll all just fall apart.
Signal has not been good. The absolute least we should expect from any "privacy oriented company" is that they're honest and fully transparent about the data they collect and store, and Signal is none of that. Since they started collecting and forever storing sensitive user data in the cloud they've refused to update their privacy policy to alert people to that data collection.
If you advertise your service to human rights activists, journalists, and whistleblowers whose freedom and/or lives are on the line you owe it to them to be extremely clear about what their risks are by using your service, but Signal outright lies to them in the very first line of their privacy policy.
This isn't "perfect being the enemy of good" this is either a massive dead canary warning people not to use/trust Signal, or it's completely immoral and irresponsible.