iLounge has looked at the new iBooks 1.1 in one of its typically excellent reviews. Here’s part of the conclusion:
Though iBooks 1.1 still has a few shortcomings by comparison with Amazon’s Kindle—the store’s smaller, you can’t zoom in on pictures in ePub books, and the wireless synchronization’s a little slower—Apple’s addition of PDF support, new font options, and additional notetaking capabilities are all strong evidence that iBooks will evolve dramatically over time to become a serious competitor to Kindle. Only two months after its introduction, it has added support for an entirely new and more powerful document format, as well as features that match or surpass ones Amazon previously held out as advantages of its software. If there was any question two months ago as to whether iBooks or Kindle was the superior iPad book reader, iBooks has certainly taken at least a narrow lead now.
See the rest of the review, including the rest of the conclusion, at the site. One of the things this, and other, reviews fail to mention is that DRMed content can only be read on Apple equipment, while other platforms, like Kobo and Kindle, allow the reader to take DRM content to almost any platform they may use in the future.