While there is no direct comparison to InfluxDB in the article, look at the disk usage and (more importantly) disk I/O utilization, which is indistinguishable from zero on the graph, whereas before it was at 20-30% with the same load.
So not on par. Much, much better.
(Of course, Prometheus and InfluxDB are not perfect substitutes for one another, so there's much more to look at than just storage engine performance.)
We do have a comparison to Influx on our website: https://prometheus.io/docs/introduction/comparison/#promethe... Which is the right choice really depends on the use case. If you're doing metrics-based operational monitoring, Prometheus is generally best.
Disclaimer: Prometheus developer.
We saw a better than 10x reduction in CPU use.
This server doesn't take any query load, but it does take the same ingestion load as the others.
(The long down time in the middle is waiting for rm -rf on the old data dir.)