It is incredibly useful on Garuda. The Sisters spawn at exactly 3 minute intervals, so what you do is the second you see garuda dissapear, cast Eye for an Eye on the tank, Sacred soil the area, Virus Garuda, and succor / heal away. By the time the next sisters spawn everything is off cooldown, and Sacred Soil helps mitigate a ton of the damage by the sisters, making it fairly easy to keep everyone alive assuming they are positioned right.