Hi Annapun,
Your question assumes that there are only 2 possible 'options' (the two books that you're considering), but it's possible that you need some other study resource instead. Before I can offer you the specific advice that you’re looking for, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied?
2) How have you scored on each of your CATs (including the Quant and Verbal Scaled Scores)?
Goals:
3) What is your goal score?
4) When are you planning to take the GMAT?
5) When are you planning to apply to Business School?
6) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich