I enjoy watching Shen games because the global ultimate adds the excitement of unexpectedly turning the tides of a losing fight. But I'm surprised at how often Stand United completes, considering it has a 3 sec channeling time.
EDIT: Emerica comments that the logistics of Shen's ultimate make it very hard to counter.
Normally Shen's ult is used from out of combat into combat, meaning no one can get him and noone can stop him, except by killing the ally he is porting to. If it is used in combat, the it is used just for the shield...[which] can NEVER be cancelled.
How does an opponent play to prevent Shen from completing his ult? What team strategies can be used to stop Shen's ult?