Was using datadog's APM to track the transactions and our API usage. But because we are using GC AppEngine, we had to use a workaround by installing the agent on a separate VM. Then we found out that we will have to pay for APM and that VM too, not just APM, so we left it.

We tried newrelic before, it was good, but datadog seemed like a complete solution (and has better design).

Actually I am surprised that there is no high quality open source APM.

Is NewRelic still investing into their APM product? I heard all original devs left. And I haven't seen any new feature in the last year's. And the last one (Error Analytics) looks clumsy and half-finished. Mobile support inexistent.

Huh? Prometheus definitely exists.

I don't find it easy to use. I want something like existing APM SaaS.

What about product analytics?

Heap is great.

We use instana.io. It's UI is clunky but gets the job done. It allowed us to troubleshoot multiple severe bugs in production which would have been hard to solve otherwise.