Once it's all 1's and 0's, it won't matter much. In the digital domain, the stability of the clock timing becomes a factor. It's called jitter and it's one of the reasons why an expensive converter is expensive, designed better to minimize jitter. But I tell ya, in the grand scheme of things, it's the least important factor to be considered when comparing interfaces.
If your audio is already digital, your best bet is to keep the path to the PC as short as possible. Don't add more electronics if you don't have to. Other than that, it won't matter.