To respond to the Mailgun developer above slash below - the InboxTrail result might not be reflective of all your service, but you're selling a premium service - 37.5% spam flagging on any of your active IPs is seriously offputting.
It's true we offer a premium product, but we do so at a competitive price. At scale, our pricing model compares favorably with Sendgrid. Our pricing strategy is all about simplicity and providing lower prices as you grow with us. We don't have any kind of feature gating pushing you into higher tiers nor do we have punitive overages.