Alan has commented on this a number of times in that DAC technology is one that is pretty mature in its evolution so when you just have a handful of companies that actually design and manufacture these products, you are going to find one of them in most any piece of A/V equipment regardless of the manufacturer. As a result, the claims by some that there is noticeable audible differences from one to another is just not founded in "real world" fact.

Changing the source equipment and speakers will have a noticeable affect on what you are hearing, not DACs.