My experience with most "As Seen On TV" items is that they often take a good concept, and manufacture it so cheaply as to make the item virtually useless. There are however, exceptions; I have heard good things about the "Magic Bullet", for example.
Look for local TV stations consumer reporters, who often test these items. A good search term is "Does it Work", especially if you put a day of the week after it, such as "Does it Work Monday", or "Does it Work Thursday".
Here's one from a station that has been reliable for me in the past: http://www.kcbd.com/story...avor-wave-does-it-work
One caveat; NEVER, NEVER, NEVER order an "As Seen On TV" item by telephone or online. Always buy it from a physical store, where you can return them if they are defective. The telesales and websites will work very hard to get you to get a bunch of "free" or "low cost" extras, where they kill in in the S&H charges.