I tried the PC-350 (owned by my friend) both at his place and also with my Essence STX.. The amp really creates a difference and is actually essential to drive such high quality headsets.. I could not afford one though because of its high cost and so i ended up buying the HD 515 G4ME.. I do not have a microphone requirement though.. It was the excellent audio quality of the 350 that made me think about them.. However am plenty happy with my HD 515 G4ME now..