I bought the car for uber, paid cash and consider it little more than tool. In 2 years and roughly 30,000 miles i have done oil,brakes, and tires. I also put away in the first couple months enough to pay cash for the cars replacement.
My car is a 2006 ( oldest year possible for uber) it has little to no depreciation left, if my circumstances were different and the car was new/not too old, i would reconsider for reasons others have stated.
To the OP, some things to consider, how close to bos/cam/brookline do you live and would you want to spend the bulk of your time in these areas. Are you available during the best times to be out there (5-9 am and 4-8 pm mon-fri and late night fri-sat night. Sunday is hit or miss all day.) anytime is ok, the hours listed are best chance of surge pricing. Figure to be vacuuming and cleaning floor mats 2x a week if you don't have the rubber ones, and want to keep the car super clean. Lastly, are you opposed to drunk college girl scantily clad and talking about inappropriate things like your not even there.