We study in this work the quality of experience of live mobile TV users in the presence of a playout buffer at the receiver side. We specifically consider an LTE network delivering both unicast and broadcast services, and study two cases: i. lossless channels where interruptions in mobile TV delivery are due to the absence of resources at the base station because they are totally consumed by higher priority real-time voice services, and ii. lossy channels, where we propose to exploit the existence of feedback channels to request, if possible, retransmission of the lost video frame. We derive in both cases several QoS metrics pertaining to mobile TV performance, such as interruption frequency and duration as well as video frame loss probability. Our results show the trends of these metrics as a function of several system parameters and yield design rules for network planning as well as for the playout buffer so as to enhance efficiently the live TV watching experience