Surely the first bit of advice in any post about analysing website performance should be: USE WEBPAGETEST

It gives you access to everything Chrome dev tools do, plus so much more:

  * speed index as a metric for the visual perception of performance
  * easy comparison of cached vs uncached results
  * operating on median metrics to ignore outliers
  * side-by-side video playback of compared results
  * different user agents
  * traffic-shaping
  * SPOF analysis
  * a scriptable API
  * custom metrics

I could go on. There's a lot of excellent performance tooling out there but WebPageTest is easily the most useful from my experience.