Simulations of relativistic heavy-ion collisions within three-fluid model employing a purely hadronic EoS and two versions of EoS involving the deconfinement transition are presented. The latter are an EoS with the first-order phase transition and that with a smooth crossover transition. Motivations and basics of the model are described. The analysis is performed in a wide range of incident energies 2.7 GeV < √sNN < 39 GeV in terms of the center-of-mass energy. Various results of these different scenarios are compared with available experimental data. Scenarios with the deconfinement transition look preferable at high incident energies √sNN > 5 GeV. Some predictions of the model, in particular, for NICA energies are presented.