Full disclosure: I am the OP and work at Mailgun This is tough for me to answer objectively, but I'll do my best. Both services offer many of the same feature

Full disclosure: I am the OP and work at Mailgun This is tough for me to answer objectively, but I'll do my best. Both services offer many of the same features and eliminate the pain of managing your own email server. Both services will achieve better deliverability at scale than managing your own server unless you know what you are doing and most people aren't interested in diving that deep into email. Mailgun is very focused on serving developers and that guides our product roadmap. Therefore, we don't offer features like WYSYWIG newsletter creation tools. We build everything API first and we strive to make them RESTful, intuitive and well documented. Admittedly, our GUI / control panel is not the strongest part of the product. We also focus a lot on incoming email and we are pretty proud of our inbound email parsing through Routes. Mailgun is owned by Rackspace (acquired in Aug 2012). Sendgrid is definitely the largest transactional email sender in the market. I recently read they do something like 7 billion emails monthly. They have more tools for non-developers like newsletter creators and support language wrappers that some developers prefer. They also offer inbound through their Parse App. Sendgrid is an independent, private company that has raised $27.4mm in funding according to Crunchbase [1]. My recommendation would be to try both - the docs are all online and both offer free plans to test with. [1] http://www.crunchbase.com/company/sendgrid http://www.crunchbase.com/company/sendgrid