Personally I find RAVE on CD better than a book. At least you can print the pages you want off, get them covered in oil & ****e then just throw them away when you're done. I paid a lot of cash a few years ago for the official LR, P38 manual and the pages were filthy in no time. Plus, it did not cover the electrics, whereas the CD does the lot.
That said, I also have a Haynes if I need to have a quick look at something. However I think Haynes have cut the content by no longer giving stripdown details for certain items, e.g. Gearboxes and simply saying "It's too difficult-see a specialist". They are nowhere near as good as they used to be.