One thing I like most about MailChimp is it has a free pricing option whereas AWeber has $1 option as a starting point. That means you can create a free account on MailChimp without giving your credit card details whereas you need to pay $1 for first month to start using AWeber. You can try AWeber by just paying $1 for first month. After that, you need to pay $19 each month.
Using the Personalize dropdown, you can insert custom snippets like your subscribers first name, or sign up date, and AWeber will automatically insert that data specific to each subscriber if we have it. If you collect first name, for example, you can send an email that says Hello Tom, or Hello Mary, or Hello John, depending upon who you’re sending to.