Trying to understand more about Rails and e-mail before beginning to set it all up. E-mail news notifications are already a big part of what we do and automating and improving that bit (currently MailChimp) is part of the reason for rewriting it all in Rails. From an editorial and business perspective, we want news e-mails going out to subscribers as soon as the story is published, especially for breaking stories, so as the service grows, we're looking at thousands of e-mails a day.
Are things like Sendgrid and Mandrill a substitute for trying to roll your own with Rails and Sidekiq/Resque/Delayed Job, or is it necessary to do something like Sidekiq + Sendgrid?
Assuming we use deliver_now + Sendgrid, does anyone know how long it takes before e-mails start hitting inboxes? Are we talking a couple of minutes or half an hour or an hour?