Just went through a solid, thorough first aid class last weekend, aimed at the kinds of injuries we could encounter on the gun range - but also in car wrecks, etc. Current theory, based on experience gained in the sandbox and elsewhere, is that the tourniquet is the first thing you do for severe bleeding. You need to know how to use it, you can't just apply it and crank it down willy nilly (because you will do damage to the limb if you do). You also add a pressure dressing to the wound. As long as the thing isn't going to be on for more than 6-8 hours, and you applied it correctly, they won't have a limb-loss issue. You don't use this for things that are not severe trauma to the limb - I mean, if a band aid, or a little pressure is good, it's good. If they're spurting blood out all over the place, or the bloods just running out of them like mad, you have severe trauma.
Even Wikipedia notes a current study that shows that "Analysis has shown that in cases of major limb trauma, there is no apparent link between tourniquet application and morbidity of the limb."
Again, correct application is key, here. Learn how to use it before you go doing it to someone in the field.
Realize that proper application of the QuikClot gauge products (they're only useful for packing the wound, in the end) amounts to practicing medicine without a license (any invasive procedure - which includes sticking anything inside of anyone... for medical purposes... - is practicing medicine!). Be prepared to deal with the consequences if you are not a doc! Same goes for darting someone's chest to relieve pressure from tension pneumothorax... You better not screw either thing up if you decided to do them to someone else...
They didn't give us any of the quick clot....they proberly knew better...don't give a Infantryman anything more advanced than a MRE heater!