On the downside, subscribers can only get the 10 titles offered in a given month, but on the upside they do get all 10 titles as DRM-free Epub for only 3 euros a month. (Technically the ebooks have digital watermarks, but that is close enough to be splitting hairs.)
I'm told the books are a mix of backlist and former best sellers, but since they are in Dutch I can't confirm that detail.
But I have been told that the titles for the first monthly bundle were provided by VBK Media, one of the larger Dutch publishing houses.
Correction: I've just been told that Elly's Choice was developed by e-commerce company Digi-Muse, and that it has the support of two leading publishing companies, VBK (representing several big houses like Luitingh Sijthof, Contact, Atlas) and Dutch Media. Thanks, Jurgen!
You can find more information on the Elly's Choice website.
Elly's Choice is in many ways similar to Entitle, a US based startup, but I don't think they have the same business model. Entitle offers a 2 ebook per month plan for $15, while Elly's Choice charges only 3 euros.
The radical price difference suggests that Elly's Choice pitches itself to publishers as a marketing and promotion service, and bills the publishers. This is very similar to services like BookBub, which charges authors and publishers for the privilege of being included in a daily email blast.