We have instances that spin up and down quickly. AWS bills by the second; Datadog billed at that time (unsure if it's changed) by the minute. This mismatch led to huge bills, such that monitoring was more expensive than the resource being monitored. It's probably fair to respond to that with RTFM. However, par for the course in the industry seems to be to adjust the bill when our mistake was made in good faith. Their response was to give us a small adjustment in exchange for signing up for additional services. More than just what happened is how it felt. It felt sleazy, and didn't jibe with the way the company was presented in the community.
As for the tech, it seemed like a quality product.
And that resulting in compromises such as high amounts of sampling, ignoring a facet of data altogether because "we won't need it if something goes wrong...", and/or using some kind of log stream processor to divert large amounts of data in S3 instead of allowing it be queried whenever you want.
As for the tech, it seemed like a quality product.