I'm finding dynamic content blocks in Campaigns to be severely lacking compared to other email campaign software I use.
Firstly, you are unable to use fields which aren't text fields as criteria, which meant I had to set up multiple workflows and workarounds to be able to segment/create the conditions for the content I needed.
Secondly, you can only add one condition for the criteria, then an "else if". In the example I am creating dynamic content for, I want to show different content based on the contact's sector. There is some crossover between the sectors, but in order to show the same block of content for multiple sectors, I have to duplicate the block, which is messy and takes twice as long to implement.
I am also working with Activecampaign, Sendinblue and Mailchimp and none of them have the above problems.