Talking with one reveiwer in the past he mentioned comparing a couple transports, one expensive, one not, while using a DAC that reclocks and could tell no difference.
I recommend reading Martin Colloms review in HiFi Critic. In a 4 page long review, he compared the Wadia iTransport to several, "regular" transports and CD players, and was SERIOUSY disapointed by the results he got.