Why does xiialive sometimes take a long time to buffer?

There are many things that can affect this scenario. First, your network internet speed. When you see you have full bars, that does not mean you have fast internet speed. You may be connected to 3G and your internet may be slow. Second scenario, radio bitrate vs. internet speed. The higher the bitrate the better the quality of sound and the faster your internet will need to be. So use your judgment...