The app itself isnt very good. The Kindle app is noticeably better, but the iBooks app is by far the best. Scrolling is much more natural on a phone/tablet than turning arbitrary ebook pages. It is odd that only iBooks offers you that option.
If you have a problem with your purchased book, dont expect any help from Kobo. I bought a book, but Kobo sent me the wrong edition ebook (no annotations, etc). After I contacted them, they pretended to be understanding and indicated that I would be refunded, and they never followed through. You will be better served finding a less dodgy company to do business with.
Stillnewguy about Kobo Books & Audiobooks, v7.10.5