At this particular event, Team EvIL and Team PnH were going head to head. The commentator did an excellent job of both explaining the game and getting enthusiastic about the action. We're somewhat familiar with the Guild Wars mechanics, but the action was incomprehensible -- while it's fun to watch the truly skilled ply their trade, it's hard to follow the intricacies of MMO as a spectator.
Guild Wars introduced an observer mode last December, but we'd have to spend a lot of time watching before tournaments like this became easily accessible. On the other hand, watching the pretty colours flash by is relaxing amidst the buzz of E3.