I also don't know much about Case, but I absolutely loved UNC's program when I visited. The directors are great and the program had probably the most welcoming culture out of all the programs I interviewed at.
Obviously this decision comes down to a lot of factors that no-one can measure for you, such as PIs, family, location, stipend, etc. If all that fails, consider differences in the medical schools!
I will say that for me personally, proximity to family mattered a great deal in my choice. Having attended schools and year-long programs far away from home, I've come to realize that all of the missed birthdays and special events do add up, even for the most independent of people. 8 years is a long time to be very far away from your loved ones! If you think this might affect your happiness and are truly on the fence, maybe Case is the way to go.