Mailchimp allows you to pull from your product database to feature products on campaigns in a very nice format along with tons of other very useful integrations, from best sellers to re-marketing along with a heap of customer journeys that are currently limited by our limited integration - in a number of cases customer receive emails with blank spots (this looks rather terrible).
Another issue is that whilst website customers are fed to the mailchimp list, in store POS customers are not meaning that only a portion of customers are added to a mailing list and manual uploads are required making the fee for 'integration' difficult to swallow.
At present even with the API setup Citrus Lime does not integrate properly so only items that have been sold will feed to mailchimp and only the data on that item at the time of sale (so if the price changes later or images etc mailchimp won't show this and often have missing info).
Having spoken to mailchimp a number of times about this they have said that there is an issue with our current integration and that with correct API integration all of the features would work and seriously increase our selling/marketing potential