It's easy-to use tool that allows me monitor my emails performance from multiple angles (subject lines etc). I can see how many people open each of them as well as which ones are most important in terms of click through rates or CTRs - something very useful when it comes time do decide what messages get sent out next! Sometimes there isn't enough data available at all times if you require this type of information so be prepared with alternative tools before using EI but overall great product & customer support! The best part about working here has been their team who have always gone above + beyond expectations whenever needed/asked by myself / other members within our office!! Would highly recommend any marketing manager looking into tracking effectiveness over your campaigns via analytics programs such as MailChimp!!