We develop and demonstrate the methodology of testing multidimensional supernova models against observations by studying the properties of one example of the detonation from failed deflagration (DFD) explosion model of thermonuclear supernovae. Using time-dependent multidimensional radiative transfer calculations, we generate the synthetic broadband optical light curves, near-infrared light curves, color evolution curves, full spectral time series, and spectropolarization of the model, as seen from various viewing angles. All model observables are critically evaluated against examples of well-observed, standard Type Ia supernovae (SNe Ia). We explore the consequences of the intrinsic model asphericity by studying the dependence of the model emission on viewing angle, and by quantifying the resulting dispersion in (and internal correlations between) various model observables. These statistical properties of the model are also evaluated against those of the available observational sample of SNe Ia. On the whole, the DFD model shows good agreement with a broad range of SN Ia observations. Certain deficiencies are also apparent, and point to further developments within the basic theoretical framework. We also identify several intriguing orientation effects in the model that suggest ways in which the asphericity of SNe Ia may contribute to their photometric and spectroscopic diversity and, conversely, how the relative homogeneity of SNe Ia constrains the degree of asymmetry allowable in the models. The comprehensive methodology adopted in this work proves an essential component of developing and validating theoretical supernova models, and helps motivate and clearly define future directions in both the modeling and the observation of SNe Ia.