>>> "You don't magically get higher deliverability only because your mail is passing through them. They don't have mythical "whitelist" slots at the ESPs. They're not even on the radar of the ESPs."

That's absolutely right, you don't. But email deliverability turned from a massive mystery and headache for us, into a sure-fire deal, the day after we implemented SendGrid. We develop translation/localization related apps, not email apps. So for us that's cool :)