It comes down to personal preference! So, when one student says “BPP is best” it could equally be the case that the next poster will say “Kaplan is better”
You cannot expect guidance on this. Why not borrow ( if you can ) a copy of both and compare for yourself – which is easier to read. They both cover the same material and are both professionally written – there really cannot be a World of difference in the content. Therefore, it must be the way the different matters are expressed.
And you may prefer the BPP way of writing to the KaPlan way. It’s personal