A white record producer signs African-American musicians, and together the foundations of rock n roll are formed.
I suppose the lesson of this biopic is that when one isn't racist in a racist world, one stands to benefit. That is the only discernible advantage that Leonard Chess (Adrien Brody) has over others, yet we don't know enough about Chess or why he is as he is.
A commonality among these characters is their penchant for extramarital sex, but Chuck Berry's prison sentence notwithstanding, this behavior doesn't make a plot-driving point or a matter of serious conflict.
In the end, Cadillac Records is a music film, with the race relations subplot only tangential, so whether or not you like this film with depend upon whether you like the musical performances by Jeffrey Wright as Muddy Waters, Mos Def as Chuck Berry, and Beyonce Knowles as Etta James. I thought they were good, but I'm not a great judge.
Overall, the plot of this film doesn't do a lot - an odd combination of social commentary about 50s race relations and interpersonal affairs - but those of you who like the origins of rock n roll might find the performances, if not the story, compelling.