I realise that the current practice software published by GMAC is GMAT Prep. However, Power Prep was their previous software.
Is it worthwhile to use Power Prep for practice tests? I hear it repeats questions from the OG.
GMATPrep also repeats questions from OG. PowerPrep does not use the real-test algorithm; GMATPrep does. PowerPrep can still be good practice for individual questions, but because it doesn't use the real algorithm, it is not as valid as a predictor of your score.