Multi-rate video scalable codecs, SVC and MDC, provide as plausible solutions to deal with heterogeneous environment of Internet. They, however, also give rise to a wide debate over which one is more efficient supporting P2P IPTV systems. Our goal in this work is to resolve the debate by providing a quantitative comparison of P2P IPTV systems given different choices of coding schemes and P2P network formations. The answer is rather subtle. MDC-based systems, though outperform SVC-based ones under certain network formation with bottleneck in terms of network throughput, suffer from a lower level of perceptual quality in terms of PSNR due to the coding inefficiency. The results drawn from this paper can be provided not only a lesson to the design of large-scale heterogeneous P2P IPTV systems but also as a strong evidence that a poor choice of codec at the higher level might over shadow the network-level designs and the codec and network formation components ought to be co-designed for optimal user experience.