I feel about eReaders the way I feel about tech-toys and video games for kids: They are a good supplement to the traditional variety of products some people thought they were destined to replace. A ball still helps a child in ways "Pong" can never replace, and the satisfying, sensual experience of reading a book entertains and informs as no backlit screen version can match. It seems that the market agrees: this year ebooks sales fell as some traditional book sellers increased capacity. Despite my initial reticence to move to eReaders, over the past few years, particularly as they have improved, I've tended to use my Kindles more and more.
The breakthrough product was last year's Kindle Voyage. The backlit screen that automatically adjusts to the ambient light is easy on the eyes, and the addition of buttons to make turning pages easier means you'll be less likely to lose your place.
Voyage was improved this year with a software update that brought markedly better page layout and typography. For the first time, reading on an electronic device felt almost comparable to a book. (By the way, the update is free. If you have a Voyage, be sure to download the upgrade!)
The 2015 Kindle Paperwhite brings many of the same benefits of the Voyage to a much less expensive device. In some ways, the new device's lighter weight makes for a more pleasurable reading experience. You get the enhanced layout, the exclusive made-for-screen-reading font, Readerly, and the option of using a "free" 3G wireless connection, in addition to wifi, to download books and magazines. (Note, however, that on both the Voyage and Paperwhite, overseas downloads of periodicals via 3G carries a surcharge.)
The Paperwhite is about an ounce heavier than the Voyage, and has no buttons. Those changes save you about eighty dollars. Most other options (3G ($70), for instance, and Ad-Free versions of the device ($20) are the same. The only difference in terms of pricing that I could see was on the 2 year replacement policy. The Voyage extended warranty costs a bit more.
A note about the "Ad-Free" version. When your Kindle goes to sleep it can display an picture (from Amazon) or a single page ad. Beyond that I don't think there is any extra advertising, so unless you really care about that one extra ad in your life, you might keep the $20 for your lattes at Starbucks. Besides, you can always pay the fee after purchase if you find you are being disturbed by the ads.
As noted, I prefer the buttons available on the Voyage and when it comes to eReaders, you can never be too light. Nevertheless, if the $80 difference is going to keep you from experiencing the eReader revolution, by all means go with the Paperwhite. I have seen rumors, by the way that a Voyage 2 is imminent. You may want to hold out purchasing your eReader until that model becomes available to see if there is any movement on price. Whether the 3G option is important to you depends on where you will be using the device. If you're on a train in the middle of nowhere, or lounging by a pool where there is no wifi and don't want to go find a signal, the extra $70 may be important to you. Otherwise, you can keep the price as light as the reader by leaving off the option.
Is the Kindle perfect? No. For one thing, no version currently on the market is waterproof. I really want one I can take in the pool or tub. Also, on the Voyage, the buttons are not customizable. The top buttons on either side of the screen go back, the bottom, larger buttons take you forward. I would prefer to have the buttons on the right side take you forward and the ones on the left take you back. Of course, I don't think they are the best way to view magazines, either. The black and white screen is an obvious limitation to graphic-oriented publications.
Still, these two devices are at the top of my gadget "must-have" list for the holidays. On a recent trip to Italy I was able to carry a stack of books in my kindle, read across the Atlantic, and even pick up a couple of extra books via 3G while sitting by the pool overlooking the Ligurian Sea. I didn't have to fiddle with passwords, or carriers, or settings. I just selected the books I wanted and pressed "buy". All in a form factor just over a half a pound in weight. Amazing, and highly recommended.