I know you get this, but when you're on AWS you don't evaluate a single piece of standalone hardware for virtually any reason. It's not even worth bothering to think about. People (again, probably not you) always have this misconception that AWS is just an expensive VPS. But anyone who's really invested in the platform (and I'm guessing they are, if they have this scale as a business problem) is using a dozen different services that play really well together in the AWS ecosystem. And that's what your engineers know, and your ops team knows. It's what finance knows. You'd need to be saving massive amounts of money to even bother considering it.