My LFS buys ORA Mandarins and before I got mine I would ask if any eat prepared foods and they always said no or they never have seen it. I had them try multiple times and no dice as well since it would have been cheaper to go ORA. There is nothing wrong with them still, its just Biota does a smart thing by training there's by raising them from day one on pellet foods so they are very healthy.
ORA Mandarins are raised on prepared foods not copepods. i just don't think ORA overly touts "they eat prepared foods" because too many people associate that with a fish that swims up and eats flakes out of the water column along side your tangs and angels. in an aquarium mandarins just wont eat as fast as dottybacks, wrasses, angels and tangs do and are outcompeted very quickly.
in a species only tank with mandarins and say seahorses, i think you'd find both biota and ORA mandarins eating pellets and frozen foods just fine. but in most peoples home aquariums, with the variety of fish people regularly keep, both mandarins will default to eating mostly copepods and eating prepared foods if they can.
the bigger picture really is the value of selecting captive bred over wild mandarins, regardless of will they/wont they eat prepared foods in an aquarium. wild mandarins typically have a dismal rate of survival coming in from the wild. lots of anecdotes of wild caught eating prepared foods, but the reality is substantially more starving wild caught mandarins perishing in aquariums.