Felt compelled to create an account to describe my experiences with Palantir as well. We tried to engage with them for some threat intel work. They set up an instance for a client and in the course of the engagement:

- they exposed our data to other clients and other clients' data to us by accident

- had significant unplanned downtime

- their platform buckled under relatively small amounts of object graph data

- provided a fat client app that was the most bloated mess of repackaged and unacknowledged open-source JAR files I've ever seen