The more expensive one is much better built. It is built by SoTech and is built to withstand just about anything. A few members of our rescue squad own them and I can highly recomend it if you are going to be using it alot. It is a very heavy and hot vest, and I have recently switched to the AeroVest from TrueNorth to test for SAR use and am also looking into
WolfGear's USAR Vest.
The lesser expenisve one I have no operational experience with, but it looks and feels well enough built for a vest that would see occasional use or reside in a trunk waiting for an emergency.
As for SpecialForces.com... they are good to go, they have great customer service and communication.