No argument that this is an upgrade to a fairly lackluster mail client. However, Airmail has all of the features listed here plus a killer iOS client, more 3rd

No argument that this is an upgrade to a fairly lackluster mail client. However, Airmail has all of the features listed here plus a killer iOS client, more 3rd party app integration, real time push notifications for Gmail (in the case if the iOS client vs the terrible default mail app), syncs settings/accounts across all clients AND its blazing fast. All of that for a one time fee vs the monthly pricing scheme here for pro accounts. I made the switch a few years ago and have never looked back.