I never had a case on mine and have dropped it countless times, never had an issue.
The chassis on the sides has some pretty bad gouges, but I have never had a crack on the screen or digitizer.
I did have to replace the 30-pin connector interface (it would charge and transfer data fine, but had some weird short-circuit where it thought an external speaker was plugged in, and there would be no sound for videos).
Was yours an OEM digitizer?
The 5S I have is on its third battery and the digitizer is starting to separate. The lightning port will only work with cables in a specific orientation, and slight jiggling causes a momentary disconnect (using actual Apple cable and charger).
