The 126 CD-Rom is not user-friendly. MB could have done a better job, but then again, it's all in understanding how MB assigns task numbers to the various repair/maintenance processes. Once you get the hang of that, it's really no big deal. My biggest gripe is the quality of the images - very poor in some cases, but acceptable in most.
From a value perspective, the CD-Rom ain't bad. $125 - $150. Try buying all of the individual paper manuals that are covered in the CD-Rom for that price - IF you can find them.
If you're looking for paper, try these sites. I have dealt successfully with only the first one listed. The other 2 have been mentioned here by mercedesshop.com members.