They're two different QA 'systems'.
The SSQA, as the name says, was/is developed for the very robust Skid Steer and it's lifting, powered implement and, especially, digging arms. It wasn't designed for a tractor's FEL but
has been adopted by many in North America due to its availability and the availability of rental implements. It is a heavier weighted system due to the attachment plate that is required on each implement. This added weight will have an effect on your FEL lifting capacity.
The Euro Global QA is a QA specifically designed for a tractor's FEL and it's comparatively 'lighter' work/design (despite what we actually ask our FEL to do :laughing

. If memory serves, it's a 'self locking/disengaging' mechanism. It is popular throughout Europe (hence the name), Aus/NZ and other countries... My friends in Pyengana use it on all of their tractors with a FEL.
All implement manufacturers are happy to provide their implements to fit whatever QA system you ask for. The choice is yours,Mate.