The iPad Kindle app was recently updated with two new features I really wanted: dictionary and search. With these updates, I think the Kindle app has officially blown past iBooks in features and practicality. I've moved to Kindle exclusively for reading books on my iPad. It does everything I need it to do. Most importantly, Kindle keeps my books in sync across other devices, some of them non-iOS like my Droid.
Search was the Kindle feature I had been coveting the most. Now that it is here, I can keep not only my e-books in sync, it's easier than ever to keep paper books in sync if I want to alternate between reading on paper and screen like I am right now with War and Peace.
When I'm done reading a paper page, all I have to do is make note of a unique word or phrase on the last page I read. When I open the book in Kindle on my iPad, I can use the search function to go straight to that term and land on the right page.
For me, search was the last bit of glue I needed to pull my paper book to e-book workflow together efficiently. It's great.
E-books really work for me. How about you?