Traditional Ad Hoc network wireless communication in the past years have contributed tremendously to the dawn of wireless mesh networks (WMNs) which have so far been able to provide a significant improvement in capacity and scalability. Routing metrics which form the basic element for the routing protocol in this innovative communication technology is a call for concern as they must take into consideration the wireless medium network characteristics in order to provide a optimum appreciable QoS performance. In the past many single-radio routing metrics have been proposed for Ad Hoc networks which are not compatible with the multi-radio routing scenario demanded by WMNs. In our work, we provide a comparative analysis of most recently proposed multi-radio routing metrics for WMNs. We begin by providing an overview of the features of a wireless mesh network thereby presenting a better understanding of some of the research challenges of WMNs. Also, since single-radio routing forms the basis of multi-radio routing, we in this regard provide a review of some single-radio routing metrics. In our comparative analysis, an overview of routing protocols for WMNs is provided enabling an understanding of the demands to be included in a routing metric to ensure efficient routing in WMNs since different routing protocols may impose different demands; we then identify the requirements of multi-radio routing metrics from which we base our comparative analysis.