Having used a few of these products before maybe I can comment.

We currently use the Hemcon pad in our FAKs for the army. They work pretty good most of the time. I also have a few QuickClot ACS (Advanced Clotting Sponges) that are super. If you can have just one item, that should be it.

The earlier QuickClot powder that the USMC first used was good but you had to make sure that you didnt breathe any of it in and if the wind was blowing you had to really get into the wound to get it in the right spot. It also wasnt that effective unless you put a bandage on it immediatly because any arterial bleeding would just push it out of the way before it became effective.

Get the ACS!