[noodles87]

might seem like a bit of a short answer but i always figure the best way to beat marines esp cc oriented ones with marines is to cram as many las and plas cannons as possible meta guns (heavy flamers have worked pretty effective for me to) plasma pistols never hurt eiher throw in a few power weapons and fists....basically anything that will ignore an armor save or causes instant death

this however only works to an extent (contradiction i know) as all this is expensive so i guess its just a case of finding a balance where you have a deacent ammount of all these goodies without being out numbered

hope i helped