+1, it really depends on how much risk you want. It's real convenient to just dip and put in the tank, but to be certain, QT is needed. That being said, I've never QT'd anything, just dipped coral before putting in the display. I never had money or room for a QT starting out (though I now think I could have gotten away with the bucket method If I tried). So now none of my fish have been QT'ed and at this point I think I have to many to take out and do, so I leave them be since they all seem fine. If you have a larger tank, I'd QT, if smaller, I might not. To me, a large tank is much more pain to work with as you have more fish and rockwork to work around, also a much greater financial investment. At that point, QT seems to make sense to me.
I'll end by saying Nobody ever QT'd and regretted it. Those who don't often get lucky, but occasionally not so lucky.