That is currently next in our pipeline for a benchmark blog post. Early results look good on both the read and write side in terms of raw performance, with the benefit of more complex queries being more easily expressable.
To add to this: We've found that the benefit of Cassandra's approach is when scaling out to 100s of nodes (which TimescaleDB currently does not support). But we found Cassandra's per node usage not that impressive. We'll have more benchmarks vs Cassandra soon (@robatticus is literally the person working on it), but suffice to say that users have already replaced multi-node Cassandra clusters (e.g., 10 nodes) with a single TimescaleDB instance (optionally adding read-only replicas for hot standbys).
