commenting based on performance from my experience

pingtopawn : 300~380 ms rarely spike
gametune : 300~380 ms occasional spike @ raids especially on heavy AoE encounters(seems their server cannot handle high bandwidth)
gamepath : 230ms constant.. cheaper then lowerping.. i highly recommend it
wtfast : 240~300 ms (only tested on trial account..never raided with it)
lowerping : 230 ~280 ms same with wtfast... only tested trial... most expensive to subscribe among all

result may vary between other individual and factors such as configuration, IP address , ISP , etc etc

try all of it and you be the judge