There was a time when people complained that the photo reproduction in the CD was not very good... which I think was from the fact that the 617 turbo book was full of many too dark photos...

All my manuals are paper...

I like the Haynes manual for some of the pictures... but it leaves some things out totally...
So you also need the Factory shop manuals... and I really prefer the paper ones.... random access is faster... LOL.. I find using PDF on my computer very very slow.... I would not own a large file which had to be accessed from a PDF file.....I also have trouble controlling the font size my printer prints with... sometimes it lets me be in charge...sometimes NOT...
Here is what I have picked up/seen to exist so far....

1. 123 chassis manual vol 1
2. 123 chassis manual vol 2
3. 615,616,617na engine manual
4. 123 heating,ac and climate control manual
5. 123 electrical manual ( I think it has the vacuum routing also)
6. 123 manual trans overhaul manual
7. maintenance manual 123

8. engine manual 617.952 turbo
9. engine manual 110 gas

The official MB manuals are not very easy to read... but they have all sorts of info not in the Haynes manual.