This thread's been resurrected a bit, but figured I'd mention that I have one, like it, and would buy it again. I can't say anything about the surface tension of the water, but here's the benefits I've seen:
*As stupid as this is, it makes it easier to clean the skimmer by providing a handle to lift the basket out and hold it while I shake stuff out over the fence
*The vortex prevents leaves, etc. from just floating there above the basket of the skimmer, they actually go to the bottom, making room for other debris
*The improved flow rate, which isn't too noticeable with the skimmer on full-suction, allows me to partially close the valve to my skimmer, diverting more power to my pool cleaner without losing skimming functionality
It's built pretty well. The only issue I've had so far is that the end-cap nuts for the long screws that help secure it to the skimmer basket came off and got lost. A quick trip to Lowe's provided some replacement nuts that should work just as well for about $2.