By virtue of being Apple's preferred book-reading platform, iBooks has quickly become one of the most popular ebook reading applications for iOS. iBooks runs native on the iPad, iPhone and iPod Touch, giving it some of the largest consumer reaches of any ebook reading platform available.

While there is no doubting iBooks' success in terms of its widespread use, compared to all of all the other reader applications we've looked at, it actually has a lot of functional deficiencies.

Apple originally designed iBooks to behave and act like a real book, and focused more on the aesthetics and UI than actual App functionality.

One of the main benefits of iBooks is that unlike the two other major ebook reading applications, Kindle for iPad and Barnes & Noble e-Reader, iBooks supports syncing of DRM-free EPUB and PDF content directly to the iPad thru iTunes.

This is an excellent feature, but essentially locks the user down to using iTunes as the primary data transfer mechanism and thus requires a host PC or Macintosh in order to maintain the library.

Additionally, EPUB and PDF content synced into iBooks' library is not accessible by other e-Reader applications. Generally speaking, every e-Reader app for iPad maintains its own separate database, and is not compatible with each other.

Unfortunately, iBooks doesn't scale very well as the size of your EPUB library increases. While iBooks is perfectly fine for a few dozen or perhaps a hundred or so books purchased from the iBooks Store or synced into iTunes, it is extremely unwieldy once you approach 300+ titles loaded into the database.

In casual testing we uploaded over 1,000 full-length EPUB novels to iTunes which we synced to the iPad. We encountered a number of connectivity/timeout issues with the iBooks sync on Windows, plus we discovered that iBooks performs badly when browsing in "Bookshelf" mode when many titles have been loaded into the application.

We found that the less aesthetically-pleasing "list" mode actually works better for browsing a large content library. Although the third, fourth and fifth-generation iPads are much faster than the original iPad and the iPad 2, caching that many titles into the database still causes the app to perform very slowly, so I wouldn't recommend using iBooks for storing your entire personal library in EPUB format.

While Apple has made a number of performance improvements to iBooks in the four years since its introduction I'd still say that the iBooks software isn't as sprightly as the others on this list.

The aesthetic focus of iBooks is also in my opinion one of its most serious weaknesses. Much time has been spent by Apple's developers on how the app looks in terms of eye-candy and very little time was spent on how well the application works for actual text reading.

The current version of iBooks has 3 color schemes (black on white, sepia, and inverted white on black) and seven font variations.

Although iBooks got a major overhaul for iOS 7 by elimination of skeumorphism from the UX, there is still no way to set iBooks to maximize the most use of screen real estate and adjust margins. Four years after release this is a huge peeve.

One thing that iBooks does that many of the apps on this list cannot do is have embedded interactive content. Most if not all of these are created using Apple's iBooks authoring tool that is specific to Apple's platform.

Many of these books are educational texts, and I haven't seen much in terms of fiction and non-fiction titles or even magazines that make use of these features. As of this writing the "Made for iBooks, Our Recommendations" section is pretty slim picking, a whole 55 titles total.

This isn't to say there aren't a lot of iBooks Author-optimized titles in their catalog if you include the educational texts, but as far as showcase works, obviously not a whole lot.

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Still, by far iBooks' best asset is the iBooks Store, which has a familiar interface similar to the App Store. It's very easy to search for content and you can get free reading samples for just about every book in the store before you decide to purchase.

Because it is Apple's official eBook reading application, it is also now the only one which offers an integrated bookstore.