I've been taking aripiprazole 20mg for quite a long time and have never noticed any difference. The amount of active ingredient is the same in the brand and generics...the only difference may be in the inert ingredients (fillers) such as cellulose, lactose, potato starch, etc.
My pdoc was giving me samples of Abilify but I couldn't afford it when he ran out. Aripiprazole costs me $70/100 tablets.