The binary and ternary mixtures considered in the present study are the most asymmetric ones for which the sound velocity and compressibility data are currently available, and their complete description, including auxiliary and phase equilibria properties, puts a challenging test for Equation of State (EoS) models. The recently proposed SAFT + Cubic EoS passes this test relatively successfully (AAD% for the single phase properties less than 6%), proving its robustness as a predictive tool. PC-SAFT appears to be the less reliable estimator of the data, whose AAD% might exceed 22%. Although the overall precision of the Soave-Benedict-Webb-Rubin (SBWR) model in predicting thermodynamic properties is better than of many popular EoS, it is not as advantageous as SAFT + Cubic (AAD% for the single phase properties less than 12%). The major difficulty of SBWR is modeling phase equilibria in asymmetric systems due to the prediction of the unrealistic U-type LLE critical loci. Nevertheless, the significant practical potential of SBWR for industrial applications should not be neglected, and this model deserves therefore further evaluation and development.