How is rexulti different from abilify?

Rexulti vs Ability: Brexpiprazole has lower potential for side effects like insomnia, nausea, restlessness & akathisia compared to aripiprazole. Compared with other atypical antipsychotics there may be lower risk for weight gain, sedation, extrapyramidal sx's and ^'ed prolactin levels. REF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4749739/. I hear that Rexulti is pretty expensive.