I use SendGrid, too. It was a no-brainer: $80 a month is cheap, I am expensive. I was quite expensive indeed dealing with persistent minor clusterflops like, e.g., automated forum spambots for the forum I host for college debaters (an old hobby) caused the BCC mailserver they were freeloading off of to have enough of a spike that a large multinational advertising company decided BCC "Thanks for paying me $30 Cindy, here's the software you just bought" emails needed to be consigned to the seventh circle of hell sandwiched between Viagra spam and their own customer support requests.