We discuss the dynamics of user handover between two coexisting wireless service providers and analyze the consequent exploitation of the offered diversity by the use of multi-standard terminals. We show that the potential capacity benefits of mobile-initiated vertical handovers (VHO) are substantial, but it is important to choose the correct VHO criteria in order to achieve optimum load balancing and equilibrium states (both globally and socially). A fast-handover scheme, based on replicator dynamics is presented, which exhibits fast convergence to the socially optimal states by allowing only a subset of the necessary VHOs among the air interfaces to take place.