A few comments…
-Are both schools affordable?
-Nobody on this site knows more about you than you do, so it is ultimately your choice.
-From your comments, it sounds like Brown is your #1
-If you are truly conflicted, can you visit both schools again this month? Spending a day at her two top choice colleges in the fall of her senior year helped my D to pick her ED school and made her feel very confident she made the right choice.
-You can also consider applying RD to both and re-visiting if you are accepted at both schools.
-Also I believe Vandy has ED2 (check the school website) which would still be an option if you don’t get into Brown ED.