A number of theoretical, empirical, and semiempirical models to predict the maximum diameter and the minimum apex height reached by a liquid drop on impact with a solid surface are assessed and compared to experimental measurements. Drop impact dynamics were measured for water-glycerol solutions with viscosities in the range from 0.056 to 0.925 Pa.s impacting from fall heights between 7.5 mm and 200 mitt. Predictions of the more complex energy balance approach models agree closely with experimental results for relatively high-velocity impacts of low-viscosity fluids; however, the analysis of high-viscosity, fluid drops at low impact velocities (where inertial deformation is small) highlights that most predictions deviate significantly from experimental results. Significantly improved predictions can be achieved through an empirical adjustment of one of the existing models.