A render using those maps I posted earlier. Scene consists of a ground object onto which 3 spheres where placed. Titanium material with 10% surface roughness used as the base material for each sphere. Late afternoon sunlight settings provide the lighting.

The bump and normal material values are set at 100%.

The displacement height is kept low to try and match the appearance of the other two spheres.

The normal mapped sphere looks to have a smoother surface than its bump mapped counterpart. The displaced (using smoothing) version is altering geometry and gives a realistic edge to the model. The edges of the bump and normal mapped spheres will always be circular.

The caustic patterns produced by  the normal and displacement mapped spheres look better defined to me.