Hi, we have books and an assessment folder at mo but I have heard from several people who've recently been ofstedded that this is looked on dimly. Also, parents only see the books and these are not marked in the way that the assessments are, ie no levels, etc. Move over to just books or just folders? Either way, everything has to go in one place. What does your dept do?
If you are switching to just one (and personally I wouldn't if it works for you just on the second hand report that Ofsted wouldn't like it) Id go for books. Folders just look, and often are, disorganised. Either way, the lack of levels shouldn't bother parents as long as marking is thorough with clear targets.
We have books and in the back of each book is a tacking sheet showing the topics covered and assessment scores for exam papers. We also take end of unit assessments which are rigorously marked. These are done on paper and have separate marking sheets which are then stapled into books.