Hi Guys,
I use both!
All my classic ships sport the dacron hinge method and most of my modern stunt ships use klett hinges. It's not a question of ability, no both systems are more than adquite for the task at hand, if installed properly!
The newer stunt ship wings wll have more of a clean cut look with the diamond edge of the flap leading edge connect to the wings trailing edge, with hinges.
Most of my classic ships that I fly have nice rounded edges. That lends itself to rounded trailing edges on the wing and flaps which is what is needed for the application of dacron hinges. I guess it's more of a LOOK thang than anything else.
Mike Clark