Significant efforts and studies were recently reported for enabling active safety, traffic management, and commercial applications in Vehicular Ad Hoc Networks (VANET), since these applications are the drivers of the recent surge in VANET research and development. However, very few research efforts considered analyzing the Quality of Service (QoS) metrics that will be available to these applications in VANET. Furthermore, although there are many proposed solutions for routing in VANET, it is still unclear as to what specific characteristics VANET routing protocols should possess, since none of the proposed solutions achieves optimum performance in both urban and highway, as well as sparse and dense environment. To shed light on these issues, in this paper we analyze some of the most important QoS metrics in VANET. Namely, we determine the upper performance bound for connection duration, packet delivery ratio, end-to-end delay, and jitter for unicast communication in typical highway and urban VANET environments. According to our results, delay and jitter in VANET would be adequate for most of the envisioned unicast-based applications, whereas the packet delivery ratio and connection duration might not meet the requirements for most unicast-based applications.