The gal and I got Kindles after the big launch and I have to say that I love mine.
The best thing is the screen. There is no glare, so you can read it perfectly in direct sunlight, like at the beach or on the deck of a cruiseship, without having to constantly squint and tilt the "book" to finish a page. That is definitely one of the huge pluses for me.
Storage is great and the free Whispernet, or whatever it is called, allowed me to get a couple of new books in about 45 seconds when I was on a trip and had finished the two I had loaded. Foreign country, port of call, just fired right up and downloaded the books with no problems what-so-ever.
They have a "resource" center of live humans at the other end of Whispernet, where you can ask questions and get real feedback answers with links to books that might help. I was having an argument here on the forum with a foreign national and I wanted some ammo to put him in his place. Typed in a couple of questions and got some links about Germany advancing into France during WW2 that were most helpful in my little battle.
Con would be that I have kind of big hands and this thing light and small, so I have to be careful with how I grab it or hold it, otherwise I hit some of buttons on the sides and flip thru 20 pages of a book or something. Kind of aggravating.
The battery life was really good when I first got it, but I have noticed that it is not as long lasting as it once was. Because of the small size and light weight, I don't imagine the battery is super hardcore, so this is to be expected.
I have downloaded, probably, 100 books and swapped them back and forth from the Kindle to my laptop and haven't had a problem.
All in all I do like the Kindle concept. It's easy to get through the airport with it, it packs and carries well without problems and there is always the option of downloading something right from Amazon's library if you have the two linked, so you are never without something to read.
That said, I don't know anything about the new units and all their pluses. I do know that my woman wants an IPad really bad.