A big thing you fight with services like AWS is a lack of transparency - everything's very opaque, and so when you have something like an IO degradation on a gi

A big thing you fight with services like AWS is a lack of transparency - everything's very opaque, and so when you have something like an IO degradation on a given node, you've got very little to go off of, and you have to try and decipher if it's that you're seeing neighbor pressure on that node, if you're on degraded hardware, or if you're just abusing the hardware inappropriately. Moving to your own hardware lets you actually reason about what's going on in a controlled environment, and at the scale that Moz is working at allows us to get hardware that's robust, well-supported, and reliable enough to have a pretty serious net positive overall.