I work at Netflix and use Atlas every day. It's our go-to performance monitoring tool, and has solved countless performance and reliability issues. It's exciting to have it open source!
I summarized it in a talk recently at Surge 2014, where I showed its role for a performance investigation, and how it is central to everything:
I summarized it in a talk recently at Surge 2014, where I showed its role for a performance investigation, and how it is central to everything:
http://youtu.be/H-E0MQTID0g?t=22m http://www.slideshare.net/brendangregg/netflix-from-clouds-t...
There's more features to Atlas I didn't mention; check out the Overview on github linked in the blog post.