It all depends on what you need to actually do. The only real weakness of Firebase is the Google lock in.
Let's say you have an object called box.
It has 3 properties, the id, it's name and it's weight.
4 months later you add a 4th property. Cost, odd records that don't have a cost just return null for that field.
It all depends on what you need to actually do. The only real weakness of Firebase is the Google lock in.