Aweber allows you to precisely know who has opened your email and what are the links that they have clicked on at a specific time. I use this email marketing platform fo rmy clients and also for my personal use too. It is best tool for affiliate marketing sales.
With MailChimp you can set automatic responders such that only a subset of your email list will receive your follow-up mails. This is based on when they signed up for your newsletter. With Aweber this is not easy to do. I use mailchimp for some of my blogs and it have some awesome designs as compared to Aweber I must say.
iContact makes it easy to manage subscribers and create attractive email marketing campaigns. You can send surveys, engage with customers, and grow your business with little fuss. It’s missing some basic marketing capabilities, though. It is one of my favorite email marketing tool.