To answer this question I talk about workmanship practices, quality of materials, and design philosophy. Under workmanship practices all hinge flaps and screws are hidden except the barrel of the hinge. Hidden hinges denote an elegant approach to any construction by caring about your technique and installation. And yes it costs more. The aesthetic gain is well worth it. Also under good practices all drain holes for any possible water intrusion around the glass or screens are hidden through the center section of the bottom rail and exits right at the bottom sill plate that the door rests on. While this also costs more it denotes good workmanship again by not having to look at dirt stains streaking down the front of your doors.
Under quality of materials and design philosophy only solid materials either 7/8 for teak or 3/4 for plastic are used. No laminates are employed to create pockets for inserts as inserts are not employed in the designs. They severely weaken the frame. Rather the screen option is installed full time and the window is lifted to expose the screen. Not having a screen insert to store means not having to find it with a hole through it later.
At the center section where the doors meet the old time tested method of having a weather strip is employed. It is 3/4 thick by 1 3/4 wide for the full height of the door. This allows for a 7/8 over lap to keep the weather out. So the doors are already 3/4 minimum thickness plus 3/4 for the weather strip for a total of 1.5 inches. This is in sharp contrast to a 3/8 rabbit leaving only a 3/8 by 3/8 lip as the structural entity not only keeping the weather out but keeping one door from buckling past the other.
Later I will talk about material qualities as they relate to strength, durability. and weight. After that we will take a long look at locking mechanisms and approaches.
Here is a link and video by Joe Cicero: