User blog comment:GimmeStarfoxWii/Exhaust vs CV for Supports/@comment-1445357-20130408165622

CV is amazing for harassing the enemy jungler, and can be used both offensively (to maintain vision of someone through brush) and defensively (to clear out FoW in case the guy you're chasing is just baiting hard). Also helps the jungler to know when exactly the enemy buffs respawn by giving vision on their camps.

Exhaust is powerful for the very short uptime it has, but well-used Clairvoyances can be even more useful throughout an entire match.