Another problem is that some potential iBookstore customers are complaining that for some titles it's cheaper to buy the physical book than the electronic equivalent.
iPad owners have also highlighted the difficulty of browsing the iBookstore, thanks to excessively broad categories and seemingly misclassified books. There are also complaints of an inadequate range of books.
Also, iBooks are at present only readable on the iPad, with iPhone and iPod touch support coming later this year in iPhone OS 4.0. Some users have also expressed a desire for support for iBooks purchasing and reading in iTunes