I've always been skeptical about this thing, but I saw it at a deeply-slashed price, so I figured, what they hey. We've used it twice in the past few days, and all I can say is, it rocks. Assuming you're going for, or are happy with, 1/4-inch thick slices of pineapple, it's really great. In two minutes or so, you get a spiral of interior flesh, sans core, from top almost to the bottom of the pineapple. And you're left with a hollow, upright pineapple shell (with the core sticking up suggestively); if you take out the core, you've got a vessel for fruit salad or one of those tropical drinks with an imbrella and four straws. Without such designs, we've been slicing off the bottom and scooping out the bit of oineapple the corer doesn't get.
Amazon sells a set of three sizes and a handle that fits on them all; the size difference is in the width of the disc that does the cutting, for use with pineapples of different widths. The single ones in stores look to be equivalent to thw widest of the set of three, and is suitable for most of the pineapples we get in mainland US.
As long as I can find $5 pineapples in Manhattan, I think we'll be using this a lot this spring and summer.