We're working on a somehow similar product that works by understanding the network traffic received and sent by your application. This means it can be language independent. http://packetbeat.com/
That's really cool! Great name, too. Probably a little less comprehensive than New Relic's offering, but I like that you don't have to do any kind of integration.
On a side note, the font you guys use for parts of your site is way too thin. It's really hard to read. See the items in the bottom/middle: http://cl.ly/image/2H0r1d1b210p
