Being written in Go is hardly some kind of magic advantage. I'd go with Ceph myself because I know exactly where I stand with it. It's also got commercial support which comes in handy.
Ceph doesn't seem to support (serializable) transactions (correct if wrong), which is kind of the whole point. In fact, how does it differentiate itself from Apache Cassandra etc? By storing arbitrary objects?
I'm no Cassandra expert, but I'm certainly under the impression that Cassandra does not offer full transactions - lightweight txns only that are atomic only for a single row.