I really don't like the KY rotary bits. The "rotation" joints can get stuck so they won't bend, and it takes you rotating it with your hands to re-hinge it. I also find the joints protrude a lot, and look like they could pinch really badly.
Regarding the first bit, it looks a little longer, but that just changes the breakover angle - some horses prefer a greater distance like that one, and some horses prefer a shorter distance, like a berry link.
Iride is correct about the difference between a french link and Dr Bristol though, the major difference is in the angle of the link.