We are heavy users of loggregator and we have the same concerns as others in the thread.
We use loggregator for:
- storing all application logs for 6 month (regulations requirement) using kafka-firehose-nozzle
- getting all platform metrics for monitoring purposes using kafka-firehose-nozzle
- getting all applications metrics to provide monitoring dashboard using kafka-firehose-nozzle and cf-metrics-refinery (see https://cloudfoundry.slack.com/messages/C6WFZ5K0F/p1531268612000101)
Another concern is autoscaler (https://github.com/cloudfoundry-incubator/app-autoscaler-release). It is relying on loggregator and I haven't seen any updates on moving out of it yet.