Going to borrow a bit from a post about NESL:
If you want to work in Boston, you're going to face a steep uphill battle. In the Boston area, you have:
New England School of Law
UMass Dartmouth (as of 2010) - though on the south shore, I imagine its grads would also look for work in Boston.
Those are just the MA law schools. Nevermind that many people may have attended UG in the area and may have gone on to high tiered schools but want to come back to Boston. Boston is a hard market to break into, if you don't have any ties to the area. Someone who went to Harvard, MIT or Wellesley and then went to an out of state Tier 1 law school, would probably be more competitive in the Boston area for firm jobs than someone who is only here to attend Suffolk. (NOTE: there are a LOT of universities/schools in the area where one may have spent his or her ug). Sounds elitist but that's the profession.
Many of the Suffolk grads I know who have law firm jobs, were those who attended the Suffolk night school and had decent day jobs. Many of the area's patent attorneys, for example, worked as patent agents or as scientists/engineers/etc. during the day. That being said, if you do well enough in school, I'm sure you can find a decent firm job or maybe a state clerkship.Just know that you'd be competing with the night school students with extended work experience and great networking opportunities.
In Chicago, you'd be competing with less schools in the direct vicinity, though you might as well consider Michigan and Wash U in the mix.
The question, I suppose, is "where do you want to live?" You will have a hard time going outside those schools' respective geographical locations.
Both are great cities. Chicago is nice in that O'Hare is right there, and when you inevitably want to get away from school, it's going to be a lot cheaper to fly out of Chicago than Boston. Not to mention, come the holidays, Logan Airport is a sea of students. On a similar note, during the school year, if you like studying at coffee shops, you'll be hard pressed to find available seating. Students fuel Boston's economy, and this is evident at any coffee shop/Panera (aka St. Louis Bread Company).
I'm a bit of a foodie and would opt for Boston over Chicago in that regard.
My advice to you would be to check out firm websites and attorney bios. Look for the grads and note their grades, prior work experience, and ug institution. If you find that the average grad of x school places better at the type of firm/job you want to be at, then roll with that school.