We’ve changed email marketing from iContact to MailChimp and, just now, Aweber. We changed from iContact to MailChimp to cut costs. We then switched to Aweber because Mailchimp will not allow you to start an Autoresponder series on an imported list PLUS, as you mentioned, Aweber has much more robust measuring/management tools. However, people should be aware that Aweber requires imported subscribers to opt-in all over again.
Double opt-in, however, ensures the emails you receive are valid and are not being used by bots and the like (remember, sending too many emails to dead email addresses is a sign of a spammer, and you do not want to be mistaken for a spammer). However, you can use tools like BriteVerify which automatically screen out fake addresses or mistakes at the point where the individual is signing up.
While all of these tactics are excellent ways to make money using email marketing, they’ll most likely fall flat without some killer email copy or content to win over your potential buyers. Check out our FREE What to Write course. You’ll learn how to craft the perfect email for every layer of your funnel, and get 45+ email content templates to copy and paste.