Simple, Scalable, Extremely Fast

No complaints here.

I run hundreds of emails through SendGrid across multiple sites every day. I have never had an issue with SendGrid but I do think they are selling themselves short on the Newsletter side of things. The email offloading via SMTP or API works great, but they could really develoup more features for their Newletter widget such as Optin Form support, HTML blocks or shortcodes instead of widgets, and default User Registration options.

All in all I trust nobody else to deliver my websites mail. SendGrid is a great product and their support is outstanding too!

Former Mailchimp Customer.