obviously haven't tried Shure's. my E2G (being entry level) still sounded amaazzzing and absolutely kicked ass in build and sound quality. hefty wire so no snapping, goes round ear and its in ear blocking loads of noise.. for the money they're brilliant. as for the PMX100's, they are amazing headphones till mine (actually MX100s) decided to break, sound quality was also immense though! not sure about the CX300's because i haven't tried them, but going by brand (good but not overly priced) it's a good bet. steve