I've tried Kindle and Nook for Ipad, and I find the formatting on Ibooks blows them away, so much so I really have a hard time with the others. Plus, and this is amazing for Apple, the Ibooks format is non-proprietary. The big Ibooks drawback is the selection of contemporary books (or recent translations of classics). I love the classics and the fact they they are so readily available on Ibooks. But I'm still shocked that nearly 9months into Ibooks Apple hasn't nailed down more content.