I have not yet observed a color difference among the DP Merrill cameras, and I have all three of them. If I were to make such a claim, I would back it up with evidence as a matter of professionalism.
When I said that DP2 exhibits lousy, sickish, puke-ish, yellow-greenish tint, somebody called me a troll. Then I went back through the long DP2 thread
and found a post (page 11, post #207) from a guy who had both, DP1 and DP2, and who also noticed the difference, with DP1 looking more natural. Also, check page 44, post #875 for horrific skin color (in the upper left corner).
Now we have another claim (Hulyss):
The DP3 Merrill's colors are more accurate (by far)
Which, by inference, means DP2 colors were not that accurate after all.
I think the jury is still out as to Sigma colors. I would expect Mr. Chambers to also back his claim by posting three identical images by the Merrill trio, "as a matter of professionalism."