With MailChimp's decision to tie Mandrill use to paid

With MailChimp's decision to tie Mandrill use to paid accounts, this is going to be a major disruption on a number of sites as I have Mandrill on several and absolutely no use for MailChimp.

Anyone used alternatives for routing mail on custom installed digital ocean/linode servers other than installing some mail software on the server? Mandrill was SO EASY to use but I can't just justify $20 a month for every server using it just to route system emails.

Appreciate any tips the community has to offer!