Mandrill

Pros

Mandrill provides a simple and well documented API and has libraries and integrations available for many major web frameworks and languages. Making use of it for simple email sends is a fast and easy process, and it provides additional functionality for black lists, white lists, bulk sends, static IPs, etc. Their dashboard makes it extremely simple to see all the emails sent to a given address along with full content and reasons why sends failed or were delayed, which is a great for debugging and testing. They also provide analytics and send, receive, open, click, and bounce rates.

Cons

The service used to be much cheaper, but costs went up sharply when it was reabsorbed back into Mailchimp. Still an excellent service, but harder to recommend without reservation.

Pros

A transactional email server is setup within minutes and available for you to send out content to your distribution list.

The application provides

- Graphs to show how many emails you're sending each day
- What countries your sending the emails to
- Open rates
- Mail clients used (useful to optimise content)
- Spam rates/unsubscribe rates
- Great delivery rates

Very cost effective.

Cons

A couple of years ago, Mandrill made it a requirement for you to have a Mailchimp subscription in order to use Mandrill. It would have been better in my opinion to keep the two applications independent, just like Sendgrid.

Whilst it doesn't make the cost materially more expensive, it does mean that you have to log into Mandrill via Mailchimp which is annoying.

Pros

This application is an addon of MailChimp and is best suited for transactional emails (automated emails, think 'forgot my password' type emails). It allows you to easily manage your sending domains , although you have to verify these before you can send emails. The best feature by far is the ability to view all emails that were sent or failed to arrive, including the contents of the emails and the reason it bounced. This allows us to quickly troubleshoot whenever we get a support ticket regarding an email that did not arrive.

During our 6 months of using this feature, there has been zero downtime.

Cons

It is more expensive than some competitors, but its pricing model is very fair and easy to interpret. It does require you to have at least a monthly subscription with Mailchimp, and if you are not using this it is more expensive.

Pros

Works well, haven't experienced any problems. Has an online GUI where you can easily find emails that were sent, easy to see blacklisted emails. Has a nice statistics page to see how your emails are doing overall. We've been delivering millions of emails in past year without a problem.

Cons

The PHP SDK I used was kinda outdated and it had little options to change the behaviour without manually changing the source. They should update the library to standards that are more current.

GUI where you can view emails, etc. sometimes is a but slow. The search filters could use a face-lift.

Pros

Mandrill is a powerful application that has proven useful for transactional email. They offer an API, decent reporting and storage of track/click data for 30 days.

Cons

As part of Mailchimp they now require both a Mailchimp and Mandrill subscription. I have no problem paying for Mandrill but I'm not a fan of this billing requirement as I don't need Mailchimp. Secondly, in the 2-3 years that I have been using Mandrill I have not seen a single feature release. I find this unusual. True, it works great as-is, but there are definitely areas that can be improved or features that can be added.