My company uses it because we run our web front ends on various cloud providers, most of whose IP space is blacklisted. I don't even bother to verify that they

My company uses it because we run our web front ends on various cloud providers, most of whose IP space is blacklisted. I don't even bother to verify that they are anymore and just assume that they are. Sendgrid gets rid of this entirely, which is a pretty big win.