i feed both...my maroon clown seems to have no preference whatsoever...i think he manages to get a few more of the pellets than the flake (which probably just means i overfeed the flake a bit) but he never misses the brine shrimp...my feeding routine is:
~8am: Flake
~4pm: Frozen (brine shrimp or bloodworms (a fw thing but he likes them)
~9pm: Pellets