The biggest question I have is what does the exit story look like? I know it's a common problem for people switching to Android from an iPhone (keeping their phone number) and not receiving any messages from iPhones as their contacts are still trying to send via iMessage.

What happens at the end of the trial when I choose it's not for me. Will I suddenly loose my ability to text with every Apple user? What about in the event of a service failure of your infrastructure (it says it talks directly to Apple's servers but does it also rely on you?)... What if Apple does go after you or makes a breaking change to the protocol?

In all those scenarios, what happens to my messages? Can I export and keep them?

I'm very interested to try but the potential to loose access even for a day or two is a really hard ask.