E-Readers definitely don't seem to be part of the younger demographic... I see more 40+ using it, but that is fine by me. I couldn't imagine trying to read on anything else when I am out in the sun
Aside from my phone, my eReader is the one thing I make sure to take when we go on holiday.
Sometimes it is interesting to see WHO latches on to them though. One of the best-used eReaders in our (extended) family belongs to my father-in-law. We bought him a refurb'd PRS-350 as a gift when they were being cleared out over 6 years ago. I figured if he was anything like my parents, he would never use it. Never heard much about it for quite some time, but when we asked how he got on with it, he was apparently taking it with him to read at the pub after work every day. He is STILL using it to this day!