The desription should be changed from 'makeing barbarian immune to mind effecting', to slightly resistance, +6 save vs mind sffecting spells , thus not making you immune just resistent to mind efecting and for me ill still drink a clarity potion just incase I roll a one.
beside the other bonus of +10 vs lawfull that maybey half enemies it works against.
About the only thing this is good for whould be +10 regenerate
Why not give it an on use power up like the potion of heroism one per day?
Or simpley give the barbarian mind immune, I play barbarian so I don't have to spend a half an hour buffing.