I have been reading books for over 42 years. I LOVE them. Biographies, business, novels, mysteries, scifi, horror, comedy . . . anything. I scare people with the amount of books (and the associated bookcases) that I own.
A number of months ago, I downloaded the iPhone version of the Amazon Kindle just to see how it works and if I would actually read a book on a small screen. Well, after a few months, I have 10 books on my iPhone and there is no end in sight.
The best feature of the iPhone Kindle (IMHO) is the ability to download a single chapter of the book to see if you like it or if it is actually lives up to its hype. Be wary — this is an addictive way to get you to try the book. I've bought all of my books this way.
Readability is not an issue. I know . . . I know — you're afraid of the small form factor. But don't worry. Remember when you went from Hardcover to Paperback? You lost 1/2 the size. The Kindle's form factor is 1/2 the size again - but you get to enlarge or decrease the size of the type, have a black, white or sepia background and read horizontally or vertically. Oh — did I add that it is back-lit? You can read in bed or in low light conditions.
The verdict? I read faster, can bookmark pages/ideas quicker, and carry my current library of books wherever I go. Not in my briefcase, backpack or purse — on my PHONE.
And it's free - you only pay (on average) $9.99 for the book (where the same physical book on Amazon might run you $20-$30).
Try it - you might like love it.