Originally Posted by WhyFi

There are plenty of article readily available via Google. If every review you've read has been negative, you haven't read any on IsoSpeed - they're overwhelmingly positive. The "device" is nothing more than a bearing - no elastomers or anything like that. It allows the entirety of the seatpost/seat tube to flex as one, from BB to saddle, kind of like a sine wave, with the bearing at the null point. In practice, I will say that it might get bouncy with choppy pedaling a little sooner than a more conventional design, but that might be the tires, too (I won't get skinnier tires on it for another month or more). And yes, most seem to concentrate on smoothing out uncomfortable jolts, but I think that's getting the narrative wrong; the biggest difference I've noticed is in handling/road-holding - the bike always feels incredibly planted.