Not really sure how big of a difference it is but watching top while listening shows 34% cpu usage, with pyradio at betwen 15-20% and pulseaudio itself at 20%+. Now those numbers dont match because watching /proc/cpuinfo shows the processor bouncing between 250 and 500. I notice no system slowdowns.

The reason for better play is pianobar uses libao/libmad with no buffer to playback audio. pyRadio uses gstreamer which utilizes a buffer allowing for brief interruptions in connection.