at Towson we use the plus/minus system, but it is not manditory. some departments require the use of it, but some leave it up to the individual professors. many professors don't use the C- (becuase in your major and some core reqs. you need a 2.0 to pass). i think the + are good

but im not such a fan of the -. I have actually had many professors do that.... it's kinda nice, but then they're less likely to curve.