So we are trying to evaluate if having multiple business units will make sense for us. Is there an objective list of features that will be available or will be missing depending on us having multiple business units ?
Or is it only the user experience that gets affected with business units ?
Have a look at this table to understand the use cases of having multiple BUs:
As far as access to features within Marketing Cloud, you can control access to all features through Roles in Administration. New Business Units will retain all features that your license to Marketing Cloud allows. Just remember that you can have one Parent Business Unit and multiple Children Business Units to manage access to your business content.
There was a different question on this stackexchange but the answer provides some helpful considerations when creating Business Units. I'd recommend reviewing the decisions in the post here.
