We also use it on a multi (postgresql) database setup where every customer has its own database. Works really good, we never had any issues with migrations and do them frequently (maybe once a week).
we use it for a fairly large postgres database (growing 4-5GB a day) and haven't had any big issues so far. currently looking at a sort of catch-22 issue at the moment where the application running flyway also reads information from the database to initialize some caches and that data is inserted and maintained by another application. this works fine on an already initialized database but not for the automated testing server where the data is wiped.
We use Flyway in a number of ways. Scripted as part of some deployment processes, included with Spring Boot applications for a RoR style migration on boot, and actually use it in Java code to manage other databases from our application during runtime.
An interesting way to use it is that you can have multiple applications that may use the same schema but are responsible for their own tables- you can specify a different schema metadata table for each application and they can generally live together fairly happily. We also have an application that 'deploys' data to target databases, so we are able to run Flyway via their Java library to make sure the target schemas are correct before running our statements against them.
Prior to Flyway I used Liquibase, which is also pretty powerful- but Flyway has just been so much more versatile- and the Spring Boot 'auto' integration has been awesome.
https://flywaydb.org/