If you want to know what a kindle is like without buying one, just download a book to your computer. All you do is go to Amazon and download the whispersync software. Once you have that on your computer, you can download any kindle books.
I have bought several books and read them on my laptop. Though the kindle screen is more reader-friendly than that of a laptop (no glare, e.g.), I found the reading on a laptop quite satisfactory, and for that reason might not buy a kindle. I'm most interested in academic/science books, but based on my experience with these, I would have no problem reading fiction as well in this format.
I'm surprised to read so much reluctance on this thread. I will very safely predict that in a few years, almost all books will be available in kindle, and within a few years after that there will be very few people claiming that reading a physical book is a unique experience that a kindle can never replace. (Sounds very reminiscent of the early 1980s, when many people were saying computers were not for the masses, that most people had no use for them). Whatever attractive features a physical book has, they are locked in; the format can't be significantly changed. In contrast, there is almost limitless change possible in an electronic format, so just in the past few years we have seen major advances in readability, and there will be more.
Here are a few advantages of the kindle, beyond the obvious one of being able to store hundreds of books in a device smaller and lighter than most paperbacks:
1) Can locate and buy any kindle book in literally seconds.
2) Can easily hold it in one hand (not so with most current laptops, of course, but that will change)
3) Can turn pages with lightning speed
4) Can highlight passages without "destroying" the book, and find these passages quickly
5) Can make a virtually unlimited number of notes in the book, again without altering or marring the text.
6) Can easily bookmark and find any number of pages in the book
7) Can move quickly between two related sections of a book, e.g., between text and endnotes or references.
One of the biggest complaints I have heard, mentioned on this thread, is that you can't give or loan a book to someone when you have finished it. I'm sure that if that becomes a big enough sticking point for enough people, that will be addressed. But keep in mind that electronic books are much cheaper to produce than the paper kind, and usually sell for much less. Most kindle books sell for around $10. Also, you can usually read a portion of the book for free, to see if you're interested.