I used Kaplan for sitting AA as this was my first exam due to exemptions.
I enrolled on the LiveOnline course which was a mixture of live lectures, revision sessions and a question based session (I was required to prepare answers to multiple questions and submit them for marking. the tutor then sent these back and went through how to answer each question during the session - I found this very helpful).
The textbooks, exam kit and pocket notes provided by Kaplan were very clear and easy to understand.
I will be using Kaplan for the remainder of my studies.
Let me know if you want any more info.
If you want detail material on topics then go for BPP and if you want to the point study material then go for Kaplan.
Both are good but they are edited in different style. A number of formulae are not defined in the same way. I read both the kits, and consolidate the information by myself.