Here's something interesting: Samsung says that in addition to Epub and PDF, Readers Hub 2.0 also supports Epub3. I can't verify the completeness of support, but if anyone could check I would love to hear what you think.
Readers Hub 2.0 also sells ebooks from Samsung's global and local publishing partners, including bestselling titles, along with illustrated cooking books and interactive reading materials for kids. There's even a publisher portal (a la KDP, Kobo Writing Life, B&N PubIt) which allows publishers to upload and sell ebooks.
This app ships on the Galaxy S3 and can be downloaded to other Samsung mobile devices from Samsung, including the Samsung Galaxy Tab 2 7.0 (the screenshot).
Samsung has been dabbling in ebooks ever since they first unveiled a set of ebook readers at CES 2010 (in the heady days of the ereader bubble). Those devices never amounted to much but they were the start of Samsung's interest in the market.
Funny story: I ended up being a volunteer hand model at the CES 2010 Samsung press conference. Even though I had never seen the ereaders before I knew more about them than anyone so I got to play with them while others shot video. It was fun.