Thanks for raising this inquiry into the differences between these two similar widgets. I believe they are nearly identical, but the Popular Content widget gives you more flexibility to adjust which content types you want to show. Popular Content uses an algorithm (see https://docs.jivesoftware.com/cloud_int/end_user/jive.help.core/user/RateorLikeContent.html), while Top Liked simply counts the content with the most number of likes in a place.
Did you have any other questions for on this?
Many thanks for your help in this matter