I like the factory book too. I have a silver colored bokk that covers 70-74. I watched it on Ebay, told about it on the forums. After it was on there for a bout three weeks I bought it.
I have a yellow covered book for 74 - 77. I also have the yellow 78 book, the yellow 78 E, F and G suppliments. I'd like to get the factory books on the H, SH, SJ and SK models.
I have the Clymer, I might even get a Haynes manual. Just to see how bad it is.