No way the price difference is only 80k when accounting for tuition difference, cost of living difference (boston vs worcester), inflation, interest on loans. In fact, looking up the Cost of attendance for both school's websites (2011) shows that its around 82,000 for tufts vs. 42,000 for umass. So again, how is the difference 80k instead of 160k (yep thats double your estimate)?
For the premed hopefuls who mentioned "quality of life", a library is a library and this is where you will spend most of your time if you want to land a residency that is competitive so spare the whole boston>worcester crap.
Worcester is a rougher area than boston and thus the hospital will most likely allow you to do more and be more independent when it comes to rotations, whereas the yuppy patients at tufts will probably shiver at the site of a medical student in the same room as them.
Finally, pretty sure UMASS is ranked higher than tufts and has better research. The only thing that I would give tufts over UMASS is the name, yes more people recognize it, but then again more people recognize georgetown over university of washing st. louis, does that mean you should pick gtown over a top 5 school??