So, I hooked up both the AQ Columbia and Colorado to the two RCA outputs of Gumby today and ran each pair into a separate input on my Conrad-Johnson CT-5 preamp. As the preamp has a remote that allows for almost instantaneous switching of inputs, and I can a do direct A/B comparison between the two on the same musical content. After very close listening, the two are very, very, close. It's difficult to distinguish any discernable difference between these two cables. If there was any difference I can discern, the Colorado might, possibly, be the tiniest bit quieter and cleaner, but it's so close so as to not be any practical difference. You're going to hear differences in mastering quality much more than you're going to hear a difference between these two. The only difference between these two cables is that Colorado uses FEP air tubes instead of polyethylene air tubes. If you're interested in these cables, as the AQ Columbia is available at Music Direct for 50% off the original retail price for $200 for a 1M pair, and Colorados is $450 for a 1M pair, I would say pass on the Colorado, and get the Columbia. Or, if you have the budget, pick up two pair of Columbia for less than the price of one pair of Colorado, and put more of these into your system. Overall verdict: its'a tossup. Go for the less expensive cable if interested. Personally, I think the AQ Columbia IC at $200 for 1M RCA is killer value, and betters any other non-AQ cable I've had in my system. These are so much better than my previous reference, Zu Mission, that its not even funny. Cheers, mateys!