how are the Audio Technica ATH-AD700, koss prodj100 and the akg k-240?  

i was actually looking for something slightly cheaper then those but i have looked at all 3 headphones mentioned above and do like them alot. 

so i have owned the koss porta pros for about one year and i would like to upgrade headphones. i have a budget of ~$100. the reason why i want new headphones is: -better sound quality -less sound leakage -some more sound isolation if it is possible at this price range -i would prefer...