From a social standpoint:
Vanderbilt has more of a reputation as a party school, but restarting your social life at a new school where everyone has already established friendships can be hard, so you may end up in a less desirable situation socially.
From an academic standpoint:
Tufts offers more bio-related majors than Vanderbilt
Tufts is a leader in integrating computers/AI into Biology. Vanderbilt is not ranked. Tufts is the NSF REU site for this area. The Allen Discovery Center is one of the top labs in the country for this area. This is the future of Biology.
http://csrankings.org/#/index?bio
http://engineering.tufts.edu/research/undergradresearch/REU
http://allencenter.tufts.edu/
From an opportunity standpoint:
Vanderbilt offers the convenience of an on-campus medical center, but Metro Boston is the top Biotech Cluster in the world - with significantly more opportunities.
Vanderbilt publishes more research papers than Tufts, but Tufts has a much higher innovation ranking (which is a measure of quality of applied research).
https://www.natureindex.com/supplements/nature-index-2017-innovation/tables/top200-institutions-lens
https://www.lens.org/lens/in4m#/rankings/global/locations
Tufts (75-90%) tends to have a higher med school placement rate than Vanderbilt (66%).
http://admissions.tufts.edu/academics/after-tufts/pre-health-information/
https://www.vanderbilt.edu/hpao/documents/2017_Annual_Report.pdf
In rankings that include outcomes, Tufts’ Biology is top ranked. Vanderbilt is not.
http://college.usatoday.com/2017/05/12/best-schools-for-biology/
https://www.collegefactual.com/majors/biological-biomedical-sciences/general-biology/rankings/top-ranked/p1.html
In STEM disciplines, one learns to make decisions made based on data and logic, not nebulous concepts such as “prestige”.