mh, i gotta just describe them briefly:
i dont hink they have much in common with opeth except for the fact that they combine clean vox and growls, accoustic parts with heavy parts. their accoustic parts are more like middle eastern stuff and dont sound very much opeth. the heavy parts are rather power metallish (not that cheesy rhapsody kind of thing). the vocals are rather midrange with (imo) kinda not so interesting growls. i would recommend you to check them out but dont expect something opeth like. also the whole atmosphere is totally different.
i am not sure about DCD because i never heard their stuff...
hope that helped..
narrot