I ended up buying an Aura online to be able to return it and get my money back if I was not satisfied (french law for online bought items). And I will in fact return it tomorrow.
The screen capacitive touchscreen is very nice, the light is good (no pinhole). In terms of contrast and screen color, the Aura is not better in my opinion than my PRS-650 or my Kobo Mini, even worse for the characters sharpness. But good enough to keep it anyway.
Then I used it with my bedside lamp and I got the
pattern problem (probably made worse by the fact my lamp is a LED lamp). It's a really disturbing pattern, the top part of the screen becomes difficult to focus on, almost painful for the eyes. The Aura (or at least my Aura) is unusable for me.
My initial plan was to get a Glo instead, then I noticed the thread on the pattern problem was about the Glo. So I'm left without a backlit ereader for now. Perhaps I'll take a look at what Bookeen has to offer...