For the most part, neither. My eInk reader is mostly used for reading public domain works and library books. My LCD reader is mostly used for reading government documents and other PDFs that have a substantial amount of text. None of this costs money. Most of my book purchases are physical: either non-reference technical literature that I am willing to pay a heafty price for but expect to be a physical copy, or used/remaindered books that are dirt cheap and that ebook prices are rarely even comparable to.

I have bought ebooks in the past, but have given up on it. It is unlikely that they will get me back either, since I don't see any positive movement on price or quality.