I have the Sony Reader Daily Edition. I LOVE it.
I actually prefer it to reading actual books.
In fact I recently downloaded the Debbie Macomber Cedar Cove series. I used to belong to the Harlequin monthly book club and I had the second series in paperback. I didn't want to read them until I had read the first books in the series, so I downloaded them. Then when I finished those I downloaded the second set, forgetting that I had them in paperback!
I never lose my place, don't have to worry about bookmarks. If a word pops up in a book I don't understand I can just highlight it and bring up the dictionary definition.
I can keep text memos in it too. I wonder how I managed before I got it
I have also been able to download a lot of the old classics that are in the public domain so they have been free to download.
I also like the fact that it supports multiple formats.
It is more expensive than the Kindle, but it is worth the extra expense.