FX8 blurb says it has a PDF reader
The FX8 hardware appears to be a standard PDF e-book reader like the other Irex products, but I don't think this is how the Jepp packaging is implemented, because if the FX8 simply carried a load of Jepp plates in PDF form, you could share them with anybody else very easily, and Jepp don't want that. So I think the FX8 product runs a custom rendering program for the proprietary format used in the Jepp plates (which are vector-based and thus not that different from PDF, but much more efficient than the ultra bloated PDF format). As an example, a whole-world subscription for Jeppview 3 comes on two CDs i.e. under 1.2GB which having seen some Jepp plates as PDFs I estimate is an order of magnitude more compact than the PDF equivalent. Also, obviously, one could not update the sub via a download... not if the download was 10GB.
What I don't know is whether the FX8 retains its old e-book functionality i.e. whether one could run e.g. the ATP maintenance manuals on it. I have one of these for the TB20 - about 500MB of PDFs.
From what I hear from the USA, the FX8 is the best implementation of a handheld "EFB" currently on the market. But the Jepp sub is awfully pricey - if you don't have a Jepp sub for the required area already.
I don't see a non-backlit reader a major issue because one needs a bit of light in a cockpit anyway, and one certainly needs light to see paper printouts
I have flown with various display devices and apart from poor sunlight readability the major issue was as night: being unable to set the backlight to a brightness exactly appropriate to the ambient conditions. Most backlit LCD devices don't go dim enough.