I like that it was easy enough when my team took ownership in creating our own campaign as well how we are able have ongoing conversations with them about what's working/not-working at any given time (this has been an issue lately).
It takes some technical knowhow but not too much - if you're comfortable using your computer then this shouldn't be hard! There aren’t many other tools out there specifically geared towards smaller brands who may want more control or don'e necessarily need all those bells & whistles available through larger vendors such us HubSpot / Marketo etc.. We use mailchimp because they were recommended by another client so now everything flows together seamlessly :).