We just released version 4 of Direct Mail. The big new features include cloud syncing/collaboration, autoresponders, and a redesign for OS X Yosemite. Companion app for iOS also available at http://directmailmac.com/stamps.
Happy to take any questions or feedback. Thanks!
I wrote an email marketing system this week for my day job against the Mailgun API to do the sending and to send to 183k recipients, it'll cost us < $80 USD. It would be even cheaper if I used AWS but we're a Rackspace shop.
(I understand not everyone out there is a programmer, but the price is very high compared)
Good luck though.