DNG vs PEF

[David Zaninovic]

So what is the final verdict on DNG vs PEF ?  What do I lose by converting PEF 
to DNG ?  Do I lose any picture information or just
metadata, like which lens was used and other things I don't really need.  I 
need size reduction from 13MB to 5MB, that is a huge
difference.  If I have to keep PEF-s then there is no reason to use DNG.