We dropped InfluxDB after they introduced their enterprise version.
Currently, we are running several nodes of Riemann/Cyanite/Cassandra.
It works very well, integration is pretty straight forward.
I've not yet used in in production, but I have kicked the tires enough to know that a) it's (much) faster, and b) I'm planning a production deployment this fall.
For the most part it's compatible with Cassandra out-of-the-box, i.e. many well-known frameworks that run on top of Cassandra "just work". The main thing it's missing is support for Lightweight Transactions (scheduled for the 2.0 release).
The dev team behind ScyllaDB is rock solid, very competent.
