Ask HN: What's better for email deliverability? Own Server/AuthSMTP/SendGrid?

We are running some experiments to decide which route to take for sending emails in our marketing automation SaaS product. I wanted to get advice/recommendation from you as well as learn from what you have experienced/decided on for "sending emails". We are experimenting to see what performs better for deliverability and here are our numbers for a recent very small test:<p>Our server: 408 sent / 60 opened - 14.7% open rate AuthSMTP: 300 sent / 23 opened - 7.67% open rate SendGrid: 206 sent / 27 opened - 13.01 open rate<p>Its cheapest for us to send email from our server, AuthSMTP is more expensive than that and SendGrid is more expensive than AuthSMTP. You really cannot compromise on deliverability but (1) costs are significantly different and (2) open's is really a partial measure of deliverability, meaning even with 7.67% open rate, AuthSMTP "may" have delivered disproportionately more than the other channels.<p>Would love to hear your experiences and suggestions.