My thoughts are that ALL jaw types are safe and secure when properly hitched... None are safe if not hitched properly.
A few times a year we will have someone post about having hitching problems only to find that they are trying to lower the king pin into the fifth wheel hitch...scary and frustrating to the user.
Most issues seem to be related to user error.
The Reese dual jaw design is my favorite, I like that you don't have to manually open the jaws, just back into them with the safety latch open and they will automagically unlatch and latch back around the kingpin. I also like the jaws pivot being physically behind the king pin when hitched...meaning the harder the truck pulls the trailer the tighter the jaws close.
B&W and Curt both have a pivot in front of the king pin when hitched. Is it safe? Yes it is...but I prefer the Reese dual jaw design.
Husky and Some Reese hitched have a single jaw design which is very nice. Gives you the security advantage of the sliding bar and the comfortable ride of the dual jaw (360°contact).
Personally, I don't own a fiver or a hitch right now. But if I were spending money I would own either a Reese or a B&W Patriot...with the edge going to Reese simply by the design of the dual jaws pivot point.
Thanks!
Jeremiah