I have always built my own ifak's, recently I purchased a few pre-built from Bear Independent! I am not disappointed. ;-)
I'm also working for myself as a firearms instructor and always keep a trauma kit at my private range when it is being used. One of the bearfak's I bought was a "guts only" kit to store in a plano container for range use.
For anyone considering getting a kit, they are well worth it. I have not found a kit as robust as these on the market for anywhere near the price they charge - including the ones I have built for myself!
In the pictures you will see 2 Bearfak's, a 3rd in a plano box, one of my self-built kits in a Condor EMT Lite bag (pictured for size comparison) and a Glock 19 blue-gun also shown for size comparison.
P.S. Bear Crew... If any of these pictures would be beneficial for marketing etc. you are more than welcome to use them - no credit needed! ;-)