This is what we were getting at the time, 2008. The left is the PDF as it came in from onebox, the right is the PDF after UpDox processed it:
http://i.imgur.com/MtrzulN.jpgThey said it was because they converted stuff to 24 bit image so that the pen and drawing tools could operate in color, and their 24 bit image had a slightly lower spatial resolution than the original fax.
But we could not stomach running all incoming faxes through a "blurring" filter, resulting in loss of legibility in some instances.
In fact if I remember correctly the blurring was fairly tolerable on screen, as long as you didn't zoom in. The real problem is if you printed a blurred fax, it was far far worse than if you printed the original. On the one hand everything should stay electronic, nothing should get printed. On the other hand, people do print stuff occasionally.
Again this was 2008, could be entirely different today. But moral of the story is even if you have an "all digital" workflow, you want to watch out for degradation in quality.
