Many have said that the F10 M5 makes an impression closer to the E39 M5 than the immediately preceding E60 M5, by ditching the E60's more avant garde lines and styling for the more direct and linear lines of the E39 generation. To us, this observation certainly has some merit, as borne out by the photo comparison below. To our eyes, the concept F10 M5 seemingly occupies the space between the E39 and E60 iterations - toning down the at-times controversial E60's curvacious and nontraditional cutlines, but adding more flow and dynamic surface changes to the E39's more classic upright design.
See also:
F10 M5 vs. E60 M5 comparison