It's a ball valve. Widely used in industry for the better part of forever. Pretty much leakproof and reliable as gravity. The nice thing about this one is that it has a spring-loaded handle so that you have to intentionally activate it- it isn't about to open on its own. And if you're worried about it loosening up and falling out, you should have the same concern for your drain plug, because they're both held in by the same mechanism. For that matter, this device gets put in once, so less chance of stripping threads, forgetting the gasket, etc. And you can always safety wire it in place. I do that to all of my vehicles anyway:
As far as that suck-it-out-through-the-dipstick-tube gizmo, have you ever removed the oil pan from a vehicle? Ever wonder where the sludge and particulates wind up? Any crap in the bottom of the pan is far more likely to get swept out through the drain hole (conveniently located at the lowest point in the pan, wonder why?) than it is to be drawn up through a tube that won't likely get completely to the bottom of the pan.
Which brings me to my one reservation about the Quickvalve. It appears to be kind of restrictive. Notice how the oil gushes out all over the guy's hand in the video? The "Quick"Valve looks to have half the diameter (so about a quarter of the cross-sectional area) of the hole it screws into. So no fast flow to sweep out the gunk in the bottom of the pan.
I'd say it's a nice idea if you don't like getting your hands dirty and fishing the plug out of the pan when you drop it because you just got scalded by hot oil.
Not a fantastic piece of can't-live-without-it hardware, but not a bad thing, either.