I have also had Saturday interviews at other programs. Less people, including faculty seem to be around on Saturday. And if you think about it, the way most programs are organized, residents take call on the weekends and so less are in the hospital. Definitely not the best day of the week to get a "feel" for the program. Maybe if you go back for a second look things may be a bit different. Good luck with your rank list! I wish this these decisions were easier.
community 🙂