used s9 with n73 and n82 ... bought it without bill for 2.2k some time ago ..initially , i thought it sounded as good as my ep 630 ..but later it was no good ..ep 630 is way better .. also not sure whethere s9 has mic inbuilt .. cos while making calls with s9 , the people on the other end complained abt my voice loss ..so for making calls it was not that good ..
the advantages of s9 are, its not noticable when ur wearing it ..and the comfort of using it in crowded places like trains etc ..and u can change tracks, volume, play pause etc with it as well .no need to reach for the phone but sound quality is not that great ..