As I stated in a previous thread, if you still want to know in four weeks, I'll have been able to burn-in my Stage IV DL3 enough to make an objective critique of its performance. You can shoot me an email and I will give you my opinion. If I don't feel it's a significant upgrade over the stock version, I'll tell you.
I did a home trial with the stock unit. While I do believe the stock version slightly improved overall clarity and opened up the soundstage (also slightly), I did not think it was worth the purchase of a new stock unit. I did direct A-B comparisons with the Rotel RDV-1093 (my GCC amp allowed me to gain match the two units, wich I ran via separate inputs and I was able to immediately switch between the two units via remote, without any delay -within the same vocal passage, and even within the same musical note). I would liken the subtle improvement to a superior cable upgrade (which, for some people, is definitely worth the additional $1,000). Keep in mind, the stock DL3 that I demod may not have been fully burned in, and I was using a $65 AQ digital cable. Also, the flagship RDV-1093 is a much better performer than any other Rotel CD players.
If what the reviews say is true (or even just some of it)the Stage IV upgrade should net a dramatic improvement across the entire frequency range.
and recommend a really really good digital cable
Check out the Stereovox XV2.