Well, I'm a big fan of my Kobo Aura H2O. As a plus, Kobo definitely doesn't grab details of side-loaded books. (They're a Toronto based subsidiary of Rakuten, and subject to Canadian privacy law.)
Kobo uses Adobe's DRM for side-loaded books. This expands the number of potential retailers you can deal with without needing to strip DRM. As a plus, this allows e-book library loans in England.
As for your Wikipedia needs:
there is a project out there that takes the (admittedly free) Wikipedia database and packages it up as several e-books. Those would work on any e-reader and the cost isn't prohibitive (about 3 euros per volume.)