Can be performant, nowadays anyway. Worked with a team who built their own implementation because Amazon's was too slow and expensive.
It's a weird model. Too small of a dataset and it doesn't quite make sense to use Dynamo. Too big of a dataset and it's full of footguns. Medium-sized may be too expensive.
Too-small seems to be the perfect use case for DDB. I need someplace to stash stuff and look it up by key. A full RDS is overkill, as is anything else that requires nodes that charge by the hour.
It's a weird model. Too small of a dataset and it doesn't quite make sense to use Dynamo. Too big of a dataset and it's full of footguns. Medium-sized may be too expensive.