We use the Mailchimp integration with Elvanto.
Elvanto allows us to mass manage the "Receive general emails" field (i.e. to turn it on or off for everyone in a certain people category). However it does not show the "Subscriptions" options in the mass manage interface so we're unable to subscribe/unsubscribe people from a Mailchimp subscription via mass manage. This makes data cleaning impossible, i.e. to mass manage a "Past Members" people category to ensure everyone in that category is unsubscribed from a mailing list.
Currently the only way to manage subscriptions is by editing individuals which is painfully slow.