I recently signed up for a newsletter service. One of their _own_ onboarding emails to me was sent to spam by Gmail. Not a good sign for their ability to deliver my newsletters to my list.
Yeah, that's pretty bad. Not always easy to say why that happened. Could be a blacklisted server but could also be the individual (learnt) behaviour of your Gmail account.
Would be nice to have Sendy added to this study.
Thanks for your suggestion! Since Sendy is using Amazon SES, it would be more of a test of the Amazon mail servers. Good idea nonetheless!