We just got off the Caribbean Princess to Panama Canal. We briefly used the medallion app texting which worked - I found it notified me, but I didn’t always notice it.
The biggest issue is messaging is buried under a menu so it’s not easy to get to. If you’re use to fast texting, this can be frustrating. It also can be inconsistent.
We have iPhones and iMessage and that gave us a few headaches until we figured it out. We had to create a text group using our Apple ID email addresses or messages wouldn’t go through to everyone (say when trying to use an associated phone number).