You can get into a lot of financial trouble with DD custom metrics, very quickly. We're talking easy five figure bills in a few days. I love datadog and appreciate how quickly their team will teach out and tell you you have a runaway bill but there's not a world in which I think the custom metrics pricing makes it usable. They know it too and they have customers that do clever thinks to use them in bursts. Prometheus is good and with AWS driving the price down, I'll be poking it tomorrow.