Amazon's two 2011 e-ink Kindles are cheaper than e-readers have ever been, partly because they display advertisements by default, and partly because the company sees Kindles as razors, and books as blades. The USD$79 model, hereafter known as the Kindle 4 (right), has hardware buttons and a 5-way button for navigating menus. The USD$99 Kindle Touch has a touch-responsive screen that lets smartphone and tablet users tap and swipe like they're accustomed to.

The argument for e-ink over reading on a phone or tablet usually centers around three points: greater legibility of text (how the screen looks in sunlight and the overall appearance of fonts), longer battery life, and focus. The new Kindles continue to excel in these areas.

Having read on devices as poorly suited to the task as Palm Pilots over a decade ago, to the bright, full-color iPads of recent years, the monochrome screen of a Kindle always sounded to me like a step backwards. Once I started using one for book reading, however, I was converted; the form factor of these Kindles is simply perfect — close to a paperback in size, but lighter. Text has physical presence, and looks more "real" than words on an LCD screen. A larger, heavier tablet cannot hope to be as immersive.

Amazon says the battery in the Kindle 4 lasts about a month (30 mins a day, or approximately 15 hours), but it's hard to be precise about units of time because the device only uses power when a page is turned. The screen consumes nothing when it's left alone or in sleep mode (where the screen displays ads unless you pay USD$30 to opt-out), although everything still looks "on". The slightly thicker Kindle Touch lasts two months.

Psychologically, this is an important difference from backlit LCD e-readers. In the middle of a page, you're able to pause, reflect, and resume reading without the omnipresent, subconscious worry of a steadily decreasing battery.

Being able to get lost in a book comes down to the reduction of distractions like battery life, pop-up notifications, and constant management of a device's weight in your hands. The final distraction for sensitive readers, odd typographical styling, is nullified by a variety of text layout options. Set and forget.

The Kindle's back is covered with a rubbery soft-touch texture, and the Touch model makes turning the page as easy as nudging the screen with one's thumb. The Kindle 4's hardware buttons, unfortunately, may not be ideally placed for some, requiring pressure inwards along the edge rather than directly downwards.

In reflection of their low prices, build quality can be imperfect and the rear panel may feel a little loose when tapped. But as a work of disposable electronics meant to replace far more than the eight books it equals in cost, all is forgiven. Whether buying literature in ebook form makes any logical sense, for close to the same price as lasting, printed editions that can be shared and passed on, is another question. But if you answer 'no', the Kindles still work with .Mobi, .PDF, and several other popular file types transferred via USB cable.