Go online and play Unneccesarily Bloody Shooty Tournament 12 against hordes of 10 year olds who do nothing but scream "noob!" down the microphone? PC.
Just so you know UT3 has incredibly crappy microphone chat so there are no hordes of ten year olds yelling on both platforms. Only people saying "Can anyone hear me?" and others typing "Yes but please don't use it there is too much static."