I think you've received sound advice already. I might just say, perhaps redundantly, that Tufts is worth it if the advantages of attending outweigh the economic costs. In some other post, although the topic was about job opportunities after finishing a PhD, someone, quite rightly, pointed out that prestige bias is important - a claim that could also be applied to PhD applications. I don't have hard evidence, but it seems that admission committees do take into account the prestige of the institutions the candidate attended; also, a good faculty and the availability of resources can help one to become a better philosopher - the Boston area seems to be a fantastic place to do philosophy and networking. I don't know how true are the statements that go along the lines of "it can be the same wherever you go, everything depends on you," they may be true, but I lean to the opposite side: tutors matter. I guess that is why people aim at top programs.
People here seem to agree here that incurring into debt by doing a masters degree, or any other graduate program, is a poor choice. I partially disagree: debt can be crippling, but I think that some debt may be compensated in the future with greater opportunities. Of course, everything depends on the amount of debt you incur. If you think that Tufts will help you to advance your career more than SFU could, then I think is worth to, at least, consider going. But if resources are really tight, that's another story.
In any case, I wish you find a wide window of peace of mind to take a decision that satisfies you.
