Outbound SMTP Service
I have a client that I host on my server that has several hundred users. These users are automatically subscribed to a digest of the announcement forums when we sign them up. They are a group of instructors for the organization so it isn't unsolicited mail. I am looking to get rid of email on my server completely by moving all of my domains to Google Apps, but I don't want to use my Apps account for this particular user because I do not want to hit the outbound server limit or otherwise upset the Google people with so much mail. The announcement forum is probably used about once a month but when it is used it can generate a lot of outbound email.
Can anyone recommend a good subscription based outbound SMTP service for this application? Preferably one with a good reputation with a high outbound server limit.
With all of these you can use SMTP as interface for outgoing emails, or you can use their API (which might have advantages in some cases).
Mandrill and Mailgun have nice "free tier" that lets you use them for free up to a certain number of emails per month, but you'll probably find (like I did) that the IP addresses they use for the free tier can be blocked a lot due to RBL's. This is becoming a major problem with Amazon SES as well. If you're serious about your email delivery you'll really really want to pay for the unique IP address so you can manage your own email reputation better.