The JD Global quick attach is a latching system for attachments (buckets, forks) on the loader of larger machines. It doesn't seem to be available for anything under a 5XXX series tractor that I can find, I assume due to the weight of the system over a traditional JD Quick Attach.
The top hooks are the same, but the loader QA tabs have ears on them to help guide the bucket into place. The lower hook up is different. Instead of removing the two lynch pins, you pull out on a lever. That disengages two pins that are perpendicular to the loader arms. Lower out of the bucket, drive over to the pallet forks. Pick the forks up with the loader, then tilt them all the way back. When they tilt back far enough, a tab on the loader arm engages the latch pin and it automatically locks in place.
I've been looking at this system lately, and it appeals to me. You only have to get off the tractor once to change attachments, and all the attachments are the same size. No more 500 series, 600/700 series, 800 series, etc. Global is a size in addition to the latch mechanism. They all interchange. All the work strain is on the locking pins, too. Since the pins run parallel to the bucket, they take just as much load when you're digging as they do if you're backdragging. It does have a linkage, albeit a heavy duty one. There's one spring that could be an issue. It weighs more than the standard JD QA also.
I like the JD QA system with the lynch pins. In my opinion, it's the best overall QA system in production. It's strong, easy, simple, and comparatively lightweight. No springs to break, no linkage to jam up, no pins to bend at the bucket. It just works. However, switching attachments means getting off the tractor twice and walking around the loader twice to install or remove the lynch pins. If you're buying attachments, you have to find the correct size. A 553 loader can't use a bucket off a 741. If you back drag with the bucket, all that strain is applied to the two lynch pins holding the lower pins in place.
I discussed this with my dealer, and for me it's a bit of a wash right now. I don't have any existing attachments to worry about converting. I don't back drag with the bucket, but I don't change attachments much either. There's not much if any difference in the difficulty level to build attachments for either hitch style.
I think if I were to buy a new tractor, I would buy the global QA. As it is now though, I'm not sure it's worth it for me to convert my current loader over to it.