I was on the beta testing team and have been using Beeper for a little over two years now.
The convenience of having an application to house all of your chat networks is amazing.
Then run your own matrix instance with these bridges that they maintain for the community.
That still doesn’t fix the e2e problem. Just because only me, and let’s hope not too many others who manage to break into the instance, can mitm everything, doesn’t make the mitm go away.
There really should be a standard, or at least a set of standards, on how to do e2e, so the bridges would only need to route the messages.