I tried maybe 15 years ago and it went about as well as you’d expect for back then. But I’m starting to get the itch again.
Have any of you tried relatively recently? How impossible is it to get reliable deliverability to gmail and whatnot these days?
It’s more of a signal that the IP address does send trustworthy email. AFAIK, IP reputation isn’t handled on a per-user basis. Domain reputation probably is.