I don't love the recent changes of PlanetScale to remove their free tier. That said, their database branching workflow is absolutely the best I've used as a dev. I can easily spin up a branch for working on a new feature and make a merge request with schema changes just like I would git. The only gotcha here is that to make it work well in CI, you have to write a few scripts with their cli to avoid doing things manually.
I've been a PlanetScale user for many months now and overall I can say it's a good, performant database.
During this time there was an incident that resulted in downtime (I think it was around an hour or so?).
Otherwise it's been running smooth otherwise.
I like some of the ideas they are pushing too. Since I'm a solo developer I can't make use of the team features but I do use branching for myself and it's a nice safety net.
Keep in mind there is no foreign key support although they are working on it. I'm looking forward to that.
Also, there is no GUI or DBMS - just a SQL console. Not sure if they plan to add that but I felt it's missing every now and then.