Efficient vertical handover mechanisms are required to provide service continuity over available and upcoming heterogeneous wireless access networks. They should provide low delays and good accuracy to meet service requirements. In the literature, proposed mechanisms rely on a rich knowledge of users' ambient environments and contexts. The outcomes are complex mechanisms that require significant amount of resources and processing time. Reputation is a rating concept already used in ad hoc security, social and business fields. It is intended to deliver fast decisions based on the analysis of users' experiences in similar conditions. In this paper, we propose the use of a reputation system to speed up vertical handover (VHO) decisions in complex wireless environments. The proposed approach can be used for initial attachments and VHO decisions. It is based on simplified rating functions reflecting a contextual QoS, experienced by previous users. Discussions and early performance evaluations are provided