The most important metrics are the traditional ones that Optics focuses on like latency percentiles and throughput. We are currently using NewRelic and Loggly. Since both the NewRelic agent and our logging system allow us to tag requests, the grouping by query structure that Optics provides, doesn't really add value. (EDIT: Further, both NewRelic and Loggly provide a better interface for zooming in on interesting areas in time.) From a operations perspective a GraphQL and a REST API aren't that different from each other that they warrant the usage of another tool.
When I tried it, the query execution view also wasn't aware of DataLoader usage. That meant, that once we started optimizing our queries, it looked like many slow parallel queries, which meant that you had to guess what was already optimized, and what wasn't.