Ask HN: APM tools

What does everyone prefer for Application Management Performance Tools? It seems like New Relic and AppDynamic cater to startups, but I'm wondering how they all compare from a large enterprise level as well. I've used CA's APM suite at a few enterprises, but I've heard good things regarding AppD.

Does anyone have experience in all three? Does anyone have any thoughts on each and where they fit or compare to each other? I'm wondering from both a devops prospective and a sys admin who may need to perform 1st level triage on an application using the tool without much context into how the app works itself.