I like how easy it was set up with my Mailchimp account! It's also super customizable so we can make our own rules/reports if needed as well which has been helpful when trying new features out or just looking at reports from different time periods (weeks vs months).
We haven't found anything yet but maybe its because of all these great reviews this tool gets compared against? Just give them some try - they have lots of integrations into other apps too such as Hubspot & Marketo etc where sometimes those tools are difficult to use without additional software outside their platform itself. Helping us organize emails sent through multiple channels within one place instead having separate folders per channel helps save tons off work by not needing extra effort sorting files manually between each app separately.