Originally posted by maxfield_photo little bits of metadata that aren't recorded in the DNG
The DNG standard supports 4 or 5 metadata formats, and those formats are extensible (different implementations can have different metadata included), but if the photo manipulation software doesn't know about a particular piece of metadata, it can't use it (and probably can't display it unless the program's GUI is designed to display an unlimited number of values).
Having said that, if you already use software that can read DNG files, and your camera can output DNG files, use DNG. DNG is a wrapper or envelope over TIFF/EP data, that includes all of the metadata your camera outputs, and the files coming out of your camera aren't missing anything that is included in the PEF file. If your camera can't output DNG, then you become dependent on third party conversion software, and you might be better off to use the software specifically designed for your camera.