We are an early customer of Tracelytics. We are also a happy New Relic customer. They are both great tools and not necessarily an "either or" decision. New Relic gives great info about what is slow from a single app perspective...being able to trace down to the layer where the issue is.

Tracelytics, on the other hand, tracks across applications and down to the individual machine serving each part of the request. This means that I can track each individual request through multiple applications/services as the request traverses different physical machines.

This has become important as our infrastructure has grown to the point where we might have 20-30 machines in a particular layer. When an app server, or network interface, or something else unforeseen goes wonky, it is extremely challenging to determine specifically what is causing the problem and where it is. With Tracelyitics, if I go into my dashboard and see that the 500 errors are all coming from a single physical server, I can take that machine out of the loop, remove the problem from the production environment, and then troubleshoot the bad box.