Kinetic roughening in two variants of a solid-on-solid model of epitaxial growth, a ''toy'' relaxation model and a collective diffusion model, is studied and compared, using extensive computer simulations in different spatial dimensions. We have studied the Wolf-Villain ͑WV͒ model and its modifications, and a full diffusion ͑FD͒ model with Arrhenius dynamics. The WV model shows nonuniversal features and its asymptotic behavior switches between the Edwards-Wilkinson type and a morphological instability, depending on the spatial dimension, a lattice coordination, or a minor modification of the model rules. The results for the FD model in 1ϩ1 and 2ϩ1 dimensions are not consistent with any of the continuum equations proposed to describe epitaxial growth; in particular, we observe too low values of the roughness exponent measured from the height-difference correlation function. In 1ϩ1 dimensions, the results obtained for both models are very similar for more than 10 6 monolayers deposited with an ''incorporation'' radius in the WV model corresponding to the substrate temperature in the FD model. Such a close correspondence is not found in 2ϩ1 dimensions. Asymptotic behavior of the WV and FD models is different in all spatial dimensions. Both FD and WV models show anomalous scaling in all dimensions studied. The anomalous scaling in the FD model is very weak ͑logarith-mic͒ in the physically relevant case of 2ϩ1 dimensions.