We moved took a large working PostgreSQL app and switched it over to CRDB and that doesn't match my experience. Our existing schemas and query patterns moved over nicely - latency for small indexed reads and writes did increase from ~1ms to ~3ms, but the max throughput now effectively unlimited since we could add capacity by adding new nodes into the cluster and letting CRDB automatically rebalance the workload. There was an increase in cost as it will need more cores, disk etc compared to a single-primary PostgreSQL, but that makes sense when you consider that every bit of data is getting stored on 5 different nodes and there are overheads to maintain the consistency.

For the highest throughput endpoints we did make some changes to be more optimal on CRDB so we could run a smaller cluster, but it didn't require anything close to a rewrite.