Delivery is more of a black art than a science and only just more a science than a poke in the dark. Having your email land in the inbox is something we constantly think about and something that is constantly being made harder.
In my opinion moving away from IP reputation makes it easier. Why? Because if you’re sending email with purpose people will read it. Good content and a reputable delivery service will give you a better chance of having your email read.
This is an interesting read – Read the article here.