As purchased, this product lacks one thing: an integral means of adjusting the gap between your laptop and the product surface. Turns out this gap is crucial to obtaining optimum performance (something indicated by a "Tip" in the user documentation). To get this product to work at its best, use some blu-tack and, at the very least, prop up the back of your laptop by a few millimetres - the increased airflow will make a dramatic difference, and reduce your laptop's temperature by several more degrees than it would without it. Actually, without this makeshift "prop," I wasn't as impressed with this device as I expected for the price.
Build quality appears to be good, with the product being well-finished, and switches and dials feel solid and not flimsy. The fans themselves whirr confidently in the background (there was an initial flutter but it's disappeared in the day I've been using it) and are unobtrusive (though certainly noticeable) even on the highest setting. The supplied USB cable is long enough for those of us whose laptops have USB sockets only on one side, rather than the rear, and is of comparable quality to the rest of the product.
And how effective is it? Well, my all-aluminium "Unibody" MacBook Pro runs pretty hot when watching movies or running Flash apps, with the heat concentrated around the bottom-left corner, the left speaker, the left-side of the keyboard, and the length of aluminium that runs along the top of the keyboard. When resting on this cooler with the fans set to max, the bottom-left corner loses much of its heat and becomes decidedly lukewarm rather than hot - almost cool, in fact. The remainder of the sections mentioned remain hot, but are definitely less hot than before. I think the difference was more noticeable in the hours following my implementation of the blu-tack "prop" at the rear of the laptop, and this has slowly diminished as the blu-tack has settled. Nevertheless, the difference is pronounced and desirable, but finding an alternative to the blu-tack that will maintain a chosen height between laptop and the cooler's surface over time is definitely on the agenda.
All-in-all, the build quality, quietness of the fans, and effectiveness of the cooling make this a worthwhile purchase at the price. Two thumbs up.