Meh, not especially. I notice the rail-like ride quality alot more than the percieved speed gain now that I've been on them a few times. Though the first time I was on them I thought I was faster, but then the first time I drank in middle school I thought I was drunk...in hind sight neither was that true. But then, I've only been given sets to ride for short periods of time and then given them back as opposed to dropping a grand and a half on a set, so I certainly feel skeptical of them.
And from the Poor, Frustrated Racers' Bible from the book Collegiate, passage 12, lines 9-13 "Thou shalt not buy the Zipps if thou art slow and rich, thou shalt work on thy motor and sacrifice, or else I shall rain great vegance upon thee - or at least great frustration on the part that I'll never own a pair of those cool things - you idiot."
Edit (I'm pretty sure there's a book for better off folks later on in that bible, I'm just not there yet.
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