Looks very promising - I can't help wonder how you can spend time building a quality product like this, then release it for free : is there a monetization strategy at some point (i.e : pro support) ?
Don't hesitate to charge a reasonable monthly fee. There's a lot of room to undercut the existing players (newrelic et al) and still make it a sustainable business.
P.S And of course the Open Source version will do the job for most people