In one South FL meet couple of years ago we did an A/B face-off of a Meridian dedicated CD player (>$2000) with my modded Toshiba 3950 DVD player (less than $200 in total, mods included). We used an A/B switch, feeding the same amp and headphones, so the only variable were the sources, well and the cables between sources and switch box. By the way the Meridian had the nominally "better", more expensive cables. Iirc, the amp was a Single power MPX3, and the headphones were HD650+Zu. Quite a resolving combo if you ask me. Granted, these were meet conditions, and the comparisons were just seconds, not more than minutes.
Playing Buena Vista Social Club on both sources simultaneously (we had two of these CDs), and switching the sources instantaneously with the switchbox, to me the Meridian and the modded Tosh were indistinguishable at the meet. What was most surprising to me, one headfier claimed that in his opion the Tosh was one ofthe best sources he had ever heard. Another headfier told me at some point he thought he detected some difference pointing to a better sound for one of the sources, and then he realized to his surprise that the switchbox had the Toshiba selected, not the Meridian. Another headfier suggested to try to hear the differences in the blackness of the background, the quiet passages, not the loud ones, that's where the differences between sources are most clearly distinguishable in his opinion. I tried and had to admit, couldn't detect differences. He grabbed the headphones and tried himself, switched the switch box a couple of times, took the headphones out and said "Can't say, I don't know what I'm really talking about..."
You can check some of the impressions at that South FL meet impressions thread
It is possible that with some other music, another recording, and in quiet, non-meet conditions, some clear difference shows. One player might more effortlessly play loud complex passages than the other, one might show more musicality, cleaner background, better dynamics... who knows. Yet for me, I really couldn't tell them apart, and some sharp ears at the meet not only had trouble distinguishing one vs. the other, accidentally seemingly even preffered the modded Tosh at some instances.
In conclusion, from that experience I left with the conviction that some inexpensive modded players can enter dedicated high-end CD player sound quality.