Given a choice of those 2 headsets (I have had both) I would choose the G35's lasted me longer and had more useful features, that and the Mic is actually pretty decent on the g35
from experience with siberia v2s i'd say only get them if they are either the USB ones, or you already have a good soundcard that you can use them with.
So many threads on this, Siberias are by far better. But you could just get none - save for AD900s + Zalman Clip on mic and twirl the cords together = bam best headphones.