From the sounds of it, and given what I know of both schools, either one would be fine for you. Detroit would be cheaper, but not by much, not enough in my opinion to make it the determining factor, especially if u liked everything else about Boston. Detroit in my opinion has got a couple of things going for it, namely, pt pop demographics. u see things here that very few other dental students see (path). u also get a HUGE volume of clinical experience, albeit mostly in basic procedures (so u will not likely get to place or observe any implants, but you will get VERY good at restoring things will amalgam and doing single crowns, dentures, etc) u'll get lots of complex prosth cases, but many times pts can't afford it, so it doesnt pan out (an obvious con) when I was interviewing for GPR posns, it amazed me just how much more clinically experienced I was compared to other students. Tufts is one of the few places that comes close, but not quite.
There are definitely ppl here (faculty/staff/classmates) rooting for you to suceed. a smaller school has advantages. ofcourse, there will be the gunnners and "faculty to avoid", but on the whole its a very conducive environ.
Tufts strikes me as a place that places a lot of pride in rank and prestige, so they will be "making sure" their students do well, if u know what I mean. I hear they also do a lot of their labwork. we still waxup our dentures, and sometimes we trim our dies, but thats pretty much the extent, no casting or waxing up crowns, etc.
I guess it comes down to, if u want to save some money, but still live in a fun city, have an awesome group of friends and classmates, graduate as an excellent clinician, while avoiding some the labwork, go to detroit.
Spend more for the much nicer collegiate city, more recognized name, stable environment (detroit's immediate future is a little questionable), more affluent pt base = more ideal tx.
other than that they are pretty comparable
the choice is yours, good luck!