I personally do not like this design since the de-cocker looks just like a safety lever but does not put the gun on safe. This is the newest action design made popular by Glock. With these pistols every trigger pull is the same and they have no external safety or decocking levers. DAO pistols depend on the long double action trigger pull to prevent accidental discharges. In a sense these are autoloaders which fire like revolvers.
Triggers vary from model to model.
Some, like the Glocks, have very light triggers. Other DAO triggers can be quite heavy and long, and can be very unpleasant to shoot. The advantage of this action is its simplicity and the fact that every trigger pull is the same. Here we get into mysticism and voodoo, and I will just give you my personal opinion and you can take it for what it's worth. I like the .45 ACP and the .357 Magnum the best.