BPP and Kaplan both are excellent publishers. However I would suggest that you should use the revision kit from the same publisher whose study text you have used as both of these institutions use slightly different techniques for solving the same set of questions. So you'll be better able to grasp on to same steps as you have studied in your study text. If you have extra time only then go for the second revision kit.
So my advice would be to use the study text and revision kit from the same publisher !