http://compass.xbox.com/assets/9d/cb/9dcb5ba2-b779-4969-b5cc-3772140825e0.pdf?n=WhitePaper_Xbox Live vs. PlayStation Network-DRAFT-V4-.pdf

the majority of scenarios for the Overall Quality category, the metrics were recorded in milliseconds. Where applicable, however, the metric was measured on a different scale (e.g., Mean Opinion Score was the measure used for the scenario on voice chat quality in order to gauge audio quality). As in the two tests above for Reliability and Speed, Xbox Live produced higher scores in Overall Quality than PlayStation Network in three out of four metrics.
