Originally Posted by mutant
Which format is easiet to crack:
ePub for Digital Editions
PDF for Digital Editions
The easiest are now the DRM schemes that have .pyw scripts to circumvent them. These include Adobe ePub and PDF (PDF is harder in that a few PDFs still fail) and Kindle for PC.
If you use Calibre, recent versions of the mobidedrm.py script can be used as a pre-processing plugin for MOBI. So once you get it working, Calibre handles DRMed MOBIs just like DRM-free MOBIs.