iPad owners have been reading ebooks with Apple’s iBooks app since that device launched. The iPhone version arrived with iOS 4. The app follows Amazon’s lead, with books redownloadable, at no extra charge, on your iPhone, iPod touch, and iPad. And since iBooks keeps track of where you are in your book, you can read a few pages on your iPhone and your iPad will automatically turn to the right page when you resume reading there.

Browsing the iBookstore isn’t as easy on the iPhone as the iPad. Our main niggle is that Apple has neglected to show prices as you browse so you have to tap into each book to see its price. The iBookstore’s biggest weakness, though, isn’t a technical one. Apple’s store includes “tens of thousands” of books, while Amazon’s Kindle Bookstore sells more than 600,000.

It’s a page turner

But assuming you can find the books you’re after, both the iPhone and iPad versions of iBooks offer a very pleasant reading experience. Each allows reading in both portrait and landscape modes. On the iPhone, you get a wider column of text, while the iPad splits the text across two virtual facing pages in landscape, or shows one page in portrait.

Both iPhone and iPad versions of the app offer a host of options for navigation and for tweaking the book’s look. Single-tapping anywhere on the text hides most of these interface elements; tapping again brings them back. On the iPhone the widgets – for changing the font size, adjusting brightness, searching the text, identifying your relative location in the book, and so on – can be distracting: it’s a lot of stuff to cram onto a single page. On the iPad, those buttons have a lot more room to breathe.

We’re a big fan of one particular iBooks feature: a small indicator telling you how many pages remain in the current chapter. Ebooks have many advantages over paper books, but quickly flipping ahead to see how many pages are left before you reach a good stopping point is one area where books beat ebooks every time. This iBooks feature is small, but brilliant.

iBooks offers great features for exploring and annotating the books you read. You can search the full text of the book for words or phrases, and jump straight to those individual passages. You can add bookmarks, highlight passages, and add notes – all of which are easily discoverable from the book’s table of contents. You can tap and hold on a word or phrase to look it up in the built-in dictionary or in Google or Wikipedia.

And, as you might expect, iBooks offers a slew of text customisations. You can choose from six fonts and 11 font sizes. iBooks also lets you disable full justification. Reading on the iPhone is, unsurprisingly, a bit taxing; the small screen requires lots of page turning no matter what font-size you settle on. But it works.

We did encounter a couple of bugs. Occasionally, books which have fancier text layouts suffer from display issues in which the tops or bottoms of characters can get cut off or split between pages. And we were occasionally greeted with a somewhat nonsensical error that the app had “Failed to load book because the requested resource is missing”. However, simply re-opening the book fixed that each time.

iBooks also supports PDF reading. In our limited testing, the PDF handling is pretty poor: you can’t annotate or highlight PDFs, the pagination feels half-baked, and large PDFs don’t resize especially well. Fortunately, there are other apps for that.