The drop away rests are more accurate for people with shooting form flaws and/or bows not tuned properly. By loosing contact as quickly as possible there is a less likely hood of a hand twist or a quick squeeze affecting the shot.

For a person who practices a lot and has a tuned bow they offer no benefit over a standard prong rest and are not as reliable or possibly consistent shot after shot.

A limbdriver kind of stradles both rests. A normal rest until the string is almost to the rest position and a drop away to allow for fletching clearance.

I personally shoot a drop away because I like gadgets and am a techno nut and until this past year shot a double prong for almost 20 yrs.