The question says it all :). I'm asking because it solved the latency problem between parents and children in the viewport and I will use this as the default blender starting argument (blender --enable-new-depsgraph).
You can watch and track any Dependency graph bugs here:
All of the tickets look resolved now. There are no disadvantages that I know of.
However you never know if somewhere is a bug or not before you test it. If you work in a production environment you probably already test everything before you use it. If your tests are fine I would use --enable-new-depsgraph with ease in mind.
The new dependency graph was introduced in 2.75, so it's had some time to get its bugs worked out by those who use it. I'd go with it if it's fixing a latency issue. "If it ain't broke, don't fix it" or in this case, "if it's fixed, don't break it." :)