Sendgrid would not reliably send our emails fast enough. We were getting queued for any gmail address we were sending too and sendgrid told us that there was nothing they could do about it. Since we have a requirement to get into peoples inbox ASAP we bailed on them as they couldn't help.

Then we went to critsend, which was great until we ran into a problem and couldn't get in touch with customer service for a week (and they never got back to us).

Then we tried Dyn since they called us up after reading a press hit and offered us a free trial period. Things were good there until we found out we couldn't deliver to comcast.com email addresses. Again, they were no help.

So we switched to Postmark and things have been awesome. Yes, you pay more than some other places, but your email gets to you recipients and it does so fast.

And yes, we had our DNS configured configured correctly for each of those services.

Good point. I looked into SendGrid, but went with PostMark afterwards. It was easier to set up.

The reason, if I recall, is that SendGrid made emails come out with a "sent via SendGrid" header, which I didn't like. To remove it, I'd have had to sign up for a paid deal with SendGrid. PostMark let me get things working first, then decide whether to pay or not.

When implementing Sendgrid, I think I spent about 30 min reading over the DNS setup docs and 30 min actually creating the records. I'm no sysadmin, but I thought it was quite easy.

Also, they have a free account which allows you to send 200 emails per month. That would allow you to try it out and then decide that Yes Virginia, it is worth the money. :)