Its not really free, its 'if you work for us, we will pay it for you, if not, then you have to pay us back'. IMO it can't hurt to get the grant, since you might get a position at a school which qualifies, work there for 4 years, and never have to pay it back. At worst, you do have to pay it back later on, but you don't have an additional 16k of debt on your back immediately out of school.