Frame geo and parts. The Quick's geo is biased towards road bikes and is built more for speed,the CX's is biased towards MTB's and built to be tougher.
Realistically speaking,unless you're going to solely be riding fast on smooth roads or only doing dirt/gravel trails one's pretty much as good as the other. Ride both and decide which feels better.
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C'dale BBU('05 and '09)/Super Six/Hooligan8and 3,Kona Dew Deluxe,Novara Buzz/Safari,Surly Big Dummy,Marin Pt Reyes,Giant Defy 1,Schwinn DBX SuperSport,Brompton S6L/S2E-X/M6L-X/S12 T Line
