This work is aimed at presenting a comparison and detailed analysis of the existing experimental data of laminar burning velocities obtained for syngas flames using the heat flux method. The consistency of these data is essential in the development, validation, and optimization of combustion mechanisms. The core of the approach is the evaluation of any variability or inconsistency among the data obtained under the same experimental conditions. The measurements have been compared both against each other and against model predictions using three detailed kinetic mechanisms available in the literature, including an updated model from the authors. Some questionable conditions have been experimentally revisited using an improved heat flux burner presented for the first time. The possible sources of uncertainty have been analyzed and discussed, and recommendations have been given toward the reduction of experimental uncertainties. Furthermore, at all experimental conditions scrutinized, the updated version of the kinetic mechanism was found in better agreement with consistent data sets compared to the previous version.