In this paper, the results of a 2D full field grain growth model are compared with several 2D mean field grain growth models (Burke and Turbull model and Hillert/Abbruzzese model), using simplified assumptions of isotropic grain boundary energy and mobility, and under the absence of precipitates. The full field model is based on a finite element formulation combined with a level set framework, used to describe the granular structure, and model grain boundary motion through a diffusion formulation. The initial digital microstructures are created using a coupled "Voronoï-Laguerre/dense sphere packing" algorithm, which allows to obey different types of initial grain size distributions, in the considered 2D context. The results show that only the Hillert/Abbruzzese model accurately describes grain growth kinetics for all considered grain size distributions. The validity of the Burke and Turnbull model is, on the contrary, restricted to specific distributions.