Hummer is safer. (just joking).Nature of impact is also very important. Recently in japan, in an accident 10-15 cars were involved where most of the cars were Ferrari and Merc involving only the car cost of few billion dollars. A week back I have seen a swift in MASS which had been hit by a truck in Durgapur Expressway (NH-2) from the back and shrinked the car to almost half. But fortunately two passengers in the front seat were unhurt due to the seat belts. So it can not be decided that this one is safer than that. But safety features included, as other honored members already mentioned, may be considered before deciding a car.
Regards.
Regards.