Actually Adderall is not racemic, since that would mean a 50/50 mix of the dextrorotatory and levorotatory enantiomers. Adderall is 75% dextroamphetamine and 25% levoamphetamine in four different salts.
Levoamphetamine is more active on the PNS, while not that active on the CNS, which causes more side effects but some people swear by it as being the best medicine. It made me feel anxious while pure dextroamphetmine did not.
However these days I take methamphetamine which feels more subtle and has even less side effects.