It is an excellent school. I am there now, graduating in June. You certainly can't beat the tuition. There are currently LOTS of renovations to the buildings and structures, which should make things quite nice. Worcester is an OK city to live in, and pretty close to Boston anyway, as well as close to oher places.
You do have to be a MA resident, I belive for 5 years, and I don't think being in college for 4 years counts, unless you legally change your residency. You have to demonstrate this on the application.
In terms of education, there is also no reason to go anywhere else, unless you are so Harvard-obsessed that it will effect you personally if you do not go there. The clinical years education is, in my opinion, equal to or superior to every other school in the commonwealth. Faculty at UMass is genuinely interested in teaching (for the most part) and you have many opportunities to gain experience. In the course of my clinical rotations, I was exposed to students from other schools in the area, and I always found that I and my classmates seemed to be more prepared, especially in terms of clinical skills. Residency directors also recognize this, and you certainly do not get short-shrifted because you go to the state U. The match list is pretty competitive, although many students choose to either stay in worcester or rank non-traditional environments higher. I know some say that you should only go to UMass if you want to go into primary care, but that is garbage. Sure, lots of people from UMass do go into primary care, but it isn't forced on you in any way. You get good exposure to primary care, and thus many people are simply drawn to it. I, for example, am going into pathology.
The only problem I have had with the school is that there has been quite a bit of turnover in terms of the faculty in the past few years. Some professors have either retired or left for places east, but the school is committed to improving this and making it a desirable place to stay. But there are lots of committed faculty members and the effect on students is somewhat negligible.
Any other questions, feel free to ask.