Sparse vs Dense dem orthomosaic

[saduka]

Hi:
I tried to build orthomosaic image on dem generated from sparse cloud and dense cloud.
Sparse dem is faster, but I am not quite sure which is better in terms of quality, because they look quite same, except details. 
Can someone kindly provide some theoretical suggestions?

[VHZN]

You can find your answer in the Agisoft's Manual:

It is recommended to calculate DEM based on dense point cloud data. Preliminary elevation data
results can be generated from a sparse point cloud, avoiding Build Dense Cloud step for time limitation
reasons.