Well, as I said, it's my own opinion, based on my own experiences, but, then again, 95% of the time I run content with tanks I know, and can go as hardcore as I want without issue, without any need for QS. And I don't like to consider it as a useful tool on things like, as noted above, Garuda EX, as adds/spiny spawn far more often than you have QS available, so I mean really, it's just a precaution that you can use once, -maybe- twice throughout the fight. I don't think it's the wrong choice, just that I personally find KF a tad more useful.