According to SNAP physicists, and the guy on the phone, light curves from type 1A supernovas indicate that the universe is accelerating. (He also says current measurements aren't powereful enough to indicate that anything other than the cosmological constant is responsible for this acceleration.) So I'm voting acceleration.
ANy attempt at refutation of this statement should be e-mailed to the guy on the phone, who declines to give me his e-mail address.