Yes, we switched metrics and logs from an Elastic stack to Prometheus/Thanos/Loki/Grafana about two years ago. On the logs side specifically, resource usage is WAY lower (300eps is like 1.5 cores and 4gb of memory), not to mention going from persistent volumes (disks) to blob storage / S3 is far cheaper and doesn't require any maintenance. Queries are slower, however, because Elastic pre-indexes while Loki searches on-demand, so it really comes down to query volume and your need for query performance (does it matter if your search takes 300ms vs 3s?). I've also found running Elastic yourself requires constant maintenance, while Loki has been very hands-off. Strongly recommend.