I'm choosing between Tufts and MGH too! The costs are similar to me - MGH is slightly more expensive than Tufts with my scholarships but I think I'm still going to go the MGH. If you haven't received a scholarship yet I sadly don't think that you will get one, they let you know when you are accepted how much they are giving you.
I'm strongly leaning towards MGH because of the interdisciplinary study, they have more simulated client experiences (where they bring actors in), and I like their electives, which are a requirement unlike Tufts. You should note that the interdisciplinary study is more hospital/medical based practice I believe, according to the students I've talked to, although simulated client experiences vary from mental health to hospital based to other I believe. Tufts is just starting their simulated client program, so you they do have that component, but I believe less so than MGH. If you're more interested in community based practice I would say Tufts would have the best connections and experiences for you. If you want to work in a hospital MGH probably has the upper hand. But both programs will prepare you for all sorts of environments, so either is a great option!
I hope this helps! Good luck deciding, I know that the Tufts deadline is today. Feel free and message me directly if you want to talk more.