I do not think levoamphetamine is useless at all in the Adderall and Adderall XR preparations, however it is more a matter of taste. Levoamphetamine acts heavily on the PNS, not so much the CNS, and can lead to a higher incidence of "body load", good and bad, as well as increased anxiety or anxious symptoms, than just dextroamphetamine. Levoamphetamine has a longer half-life, and I would bet, despite no experience with pure dextroamphetamine, it helps aid in longer acting appetite suppressant effects, which can be good or bad depending on your reason(s) for use. Levoamphetamine in combo with dextroamphetamine, I would bet, also, helps light a fire under one's ass, and keep that fire going for a longer period of time, and due to increased action with norepinephrine likely helps with fibro-variety pains and neuropathy better than pure dextroamphetamine. I take Adderall XR daily, and while I am not completely satisfied with the duration of action (still too short), I would not trade it for any other amphetamine preparation, though I have thought about the subject before. I like the idea of Dexedrine or Desoxyn, but I honestly don't think they would be superior for my needs and wants, therapuetically and recreationally.