Response Modeling Methodology (RMM) is a new empirical modeling methodology, recently developed. In this paper, a new structured procedure to compare relational models, in terms of goodness-of-fit and stability, is developed and applied to evaluate three types of models: Those obtained by TableCurve2D (a dedicated software for relational modeling), acceptable models recommended by DIPPR (a widely used database for constant and temperature-dependent physical properties), and models derived by RMM. For four pure substances (oxygen, argon, nitrogen, and water), model comparison had been conducted on 14 temperature-dependent physical and thermodynamic properties. Summary tables of ranking the various models are provided. Detailed results are reported in this paper for water. The three variations of the RMM model (two-, three- and four-parameter models) compare favorably with others, both in terms of goodness-of-fit and stability. The unique desirable properties of RMM models are discussed.