The advantages are: I can take the iPad with me and have a choice of several things to read, without access to the internet (except for Kindle Cloud). (I've got to learn how to move a book from Kindle Cloud to regular Kindle.) Most classics are free - I've downloaded Persuasion by Jane Austen to read at some point, as well as Uncle Tom's Cabin, and intend to download others in the future.
The major disadvantage is that most more recent books cost. They cost more than I usually pay for real books - usually those acquisitions are either yard sale, good price on eBay, or - checked out from the public library. I paid too much for the book, and realized afterward that I would never have spent that on a real book. It was a matter of being caught up in the moment.
There's also a kind of odd feeling at moving electronic pages. I like real pages, the kind that have texture under the fingertips, and that you can sense the roughness of the paper with.
I do think, however, that books will eventually become obsolete - part of the major transformation of our world to an electronic world, which carries great negatives along with the excitement and learning opportunities of the worldwide web. That's another post entirely. Maybe during spring break.