Are Chaplygin gases serious contenders to the dark energy throne?

We study the implications on both background and perturbation evolution of introducing a Chaplygin gas component in the universe's ingredients. We perform likelihood analyses using wide-ranging, SN1a, CMB and large scale structure observations to assess whether such a component could be a genuine alternative to a cosmological constant. We find that current data favors an adiabatic Chaplygin gas with behavior akin to a cosmological constant.