We have an app on Heroku and obviously the writing is on the wall there. We looked around a bit and picked Digital Ocean as our next host:

* their app hosting product is similar to Heroku.

* very easy onboarding and controls for modest complexity apps. Unlike the extreme hoop-jumping required to do anything on one of the major cloud providers.

* everything looks reasonably up to date.

* it's an actual operating profitable company that's been around a while and probably will be for a long time... not a startup burning capital.

That said, this magic containers thing looks more analogous to Google Cloud Run, which I think is an absolutely fantastic offering. Unlike almost everything else out there, Cloud Run and presumably Magic Containers can do things like have a whole bunch of versions of your app up and running ready to come to life when a request arrives, but scaled to zero in the meantime. This category of hosting should be far more popular than it is, and it is wonderful to see another company offer it.