I'm going to wade into this because I'm an ebook convert.
Between us, hubby and I have two e-readers. Theoretically the Sony e-reader is mine and the Kindle is his, but some e-books are only available in epub format or Kindle format, so having the two devices means we have a broader range of e-books available to us (yes, I know there's conversion software out there. Haven't gone down that route).
The Sony is the pocket version, about two years old. It came with a cover that makes it look more like a traditional book. I like the e-ink. I can take it on holiday and sit by the pool in blazing sunshine, and still see the screen. I think the Sony is more aesthetically pleasing than the Kindle. However, epub e-books in general are more expensive than Kindle books. Though this is why my royalties from Kindle sales are far less than those from epub sales...
My Sony will not 'annotate'. The Kindle will. You can put as many notes and marks as you like on Kindle versions.
Both devices let you put bookmarks in. So it possible to have a dozen books open at once, with your place marked in each. But you do have to remember to 'remove' the bookmark when you start reading again, or else it will still be holding your place there.
I like the fact that both devices are compact and light. I do most of my reading on my commute, and the e-reader is far easier to carry around than a book is. And if I finish a book on the way to work, I can just start the next one, without having to carry around a second book, just in case.
They are also much more convenient for taking on holiday. We used to pack a dozen books between the two of us for a 2-week break, which got rather heavy. Now we just take the two e-readers (and maybe a paperback each, just in case).
I like the fact I can lay the e-reader flat on the table when I read during my lunch hour. No more spilled soup because I'm trying to eat one-handed.
Buying books is very convenient, the Kindle more so than the Sony. The Kindle is literally one click. Go to amazon and click on the 'buy' button of the e-book you want. Next time you turn on your Kindle, the book is waiting for you. Or, if you have a wifi Kindle, you don't even need a computer - just go to the Amazon page on your Kindle, and buy books directly through the device.
The Sony's slightly more complicated, as you get 'reader library' software with it. To buy an epub book, you have to click on the book you buy to download it into your 'reader library', then plug the device into the PC through a USB port, and drag and drop the book from the reader to the device.
The reader serves as a backup, as all books stay there unless you delete them. With Kindle, your purchased books remain in cyberspace, on your Amazon account, so you never lose them.
Being mistrustful of technology, I also have other backups. All ebooks for both Kindle and Sony are backed up in files on our main home PC, and also on the external hard drive we have (just to be extra cautious). So what I tend to do when I've read a book is remove it from the device and keep it stored on the backup PC and external drive, just to avoid scrolling through hundreds of books for the one I want to read.
However, I will also say I haven't stopped buying print books. I'll go to a signing session and buy the signed copy. I'll browse through Waterstones and find three books in the 3-for-2 sale I think look good. Or, the e-book is more expensive than the print book (this is down to the publishers - some of them decide to price the e-book at the hard cover cost. I think this will change as the publishing industry becomes less suspicious of the digitial publishing age).
But space is a genuine issue. Our house is literally full of books and we are running out of space. The e-readers allow us to carry on buying all the books we want, without having to find space on one of the already-groaning book shelves (not counting the boxes of books in the attic).
Yes, buying e-books can be expensive. The books themselves are mostly cheaper than print, but you see so many books that are less than a pound, and they are so easy to buy, you end up taking chances on books that you probably wouldn't if you saw a paperback version priced at £6.99.
A lot of people dislike the concept of e-books, before they've actually tried them. Generally, when people discover the joys of e-readers, they realise they are not such evil things after all.
But in my view, there's still room in publishing for both print books and e-books.
Shara