Interesting!!!
I agree with the above, however when it came to me and chemistry i started half a term behind coz my timetable dude is a spastic, anywayz so the excel books are the best, however my prob is that the recent Excel for Prelim. Chem doesnt cover Polar Molecules, that i know of and also the book helps if your teacher follows the textbook, in order of topics better that way.
With Biology i would recommend the excel book however, i have realised that allot of your knowledge learnt in Bio, is of being at class. So the excel is mainly for revision.