We use Google Apps for internal email and have nothing but good things to say about it. We use MailGun for everything else (transactional's and to send from ou

We use Google Apps for internal email and have nothing but good things to say about it. We use MailGun for everything else (transactional's and to send from our internal email marketing app). It's cheap'ish, stable, and the API is rock soild. I recommend them to anyone who asks.