I'm a ferocious reader. One of my favorite places to hang out is Barnes & Noble, where I can sip coffee and read the first chapter of new books I'm "investigating" for purchase. On business trips, I'll usually read one book on the flight out and one on the flight back.

E-book readers are especially handy: They are light enough to slip into a laptop bag, yet provide access to millions of books at the touch of the screen. Recently, I decided to test four new models to see which offered the most flexibility, book selection, add-on features (likes movies and music), and the best overall value.

E-book readers tend to fall into two distinct categories. The Kindle Fire HD 8.9 ($399) and the Barnes & Noble HD+ ($179) are multi-purpose e-readers that run Android OS. Like the Apple iPad 4, they double as a mobile business device for checking email, browsing the Web, running apps like Evernote, and keeping you on schedule. The downside: They do not use e-Ink, the "virtual paper" tech that makes an e-book easier on the eyes.

The second category is what I call a dedicated reader. The Kobo Aura HD ($170) and the Sony Reader ($130) do not run on a standard OS like Android, but they do use e-Ink. The screen resolution is technically lower, but e-Ink smoothes the page for easier reading. Technically you can browse the Web and check email, but they tend to run too slow to make those tasks worthwhile.

This debate over screen resolution is incredibly important if you're in the market for a digital reader. The Nook HD+ runs at 1920 x 1280 pixels or 256 PPI (pixels-per-inch)--and the Kindle Fire 8.9 HD has similar specs. Meanwhile, dedicated readers like the Kobo Aura HD run at 1440 x 1080 pixels and 265 DPI (dots per inch). With PPI, you can measure the pixels in a row. With DPI, it's a bit more complicated. The "dots" form into a pixel.

So which is better? There's no contest: The dedicated readers look incredibly sharp. It's more of a decision between multi-purpose readers that you can use for other tasks but are harder on the eyes, or a dedicated reader that makes an e-book page look like real paper.

Kindle Fire HD

To test them, I started with the Kindle Fire HD 8.9. Amazon also makes a smaller Fire HD version that has a 7-inch screen and costs only $199, plus several e-Ink models that cost even less. The key feature on the Fire HD 8.9 is a carousel view that automatically puts recent content on the home screen. If you read a book, then check -mail and watch a movie, this activity shows up in the carousel for easier retrieval. The Kindle offers AT&T mobile broadband for only $50 per year. The Fire HD 8.9 weighs 20 ounces and is .35-inches thin. It's fast enough for just about any media you consume.

After reading two chapters of the book Bunker Hill: A City, a Siege, a Revolution by Nathaniel Philbrick, I felt the screen start to wear on me a bit. The display is crisp, but there's a glowing aura (ahem) from the LCD screen. That's handy for a dark airplane or in a hotel room before bed, and great for HD movies, but not exactly paper-like.

Barnes & Noble Nook HD+

Next, I tried the Barnes & Noble Nook HD+. (Side note: I'm not a fan of these weird naming conventions. The HD+ name doesn't really say anything other than "higher price" to me.) Still, the Nook HD+ is an outstanding multi-purpose reader. The 9-inch screen is colorful and bright, and, at just over 18 ounces, the Nook HD+ is lighter than the Kindle Fire 8.9 but has the same screen size.

A key feature of the $269 Nook HD+: For those trying to balance work and personal life, you can have profiles for your work account and personal life (and for each family member). Books you want to read on the plane pop up instantly for your work profile, for example. The Nook HD+ lacks the vast ecosystem of Apple or Amazon, though. So, if you're looking to rent a movie and then pop up an app on your Xbox 360 at home to watch it there, you're out of luck.

Kobo Aura HD

Meanwhile, the Kobo Aura HD is an outstanding dedicated reader. I loved reading most of Bunker Hill on this e-reader, and my eyes never felt any strain from the display. I can't say I missed the email and browsing features, either. I tend to use my iPad 4 for that anyway. At 8.4 ounces, the Aura is light enough to take with me on trips, along with a laptop and the iPad. It's ideal for business users who want to read and not be distracted.

The $169.99 Aura HD has the largest e-Ink screen around, at 6.8 inches. The 1GHz processor is fast enough to keep up with book pages, but still not quite up to speed for Web browsing, especially since the e-Ink display tends to flicker quite a bit.

Sony Reader

There's one spec I really liked on the Sony Reader, even though it is the least feature-rich of the bunch: the low $129.99 price tag. This e-Ink device does not quite match the screen quality of the Kobo Aura HD, but I still prefer the digital paper tech to the two readers with LCD screens. For a bit of flair, you can get a Reader in stark red to stand out from the crowd. And, the Reader syncs with Evernote for saving notes. Still, the Reader doesn't really win any points with me considering the Kindle Paperwhite costs just $119.

And the Winner Is...

So which one gets the final nod? I really liked the profiles on the Nook HD+ and the colorful, crisp screen. The Amazon Kindle Fire 8.9 has a better ecosystem for media. (It's starting to rival even the Apple iPad.) Both are outstanding tablet readers. But for my goal of reading books, I'll keep turning pages on the Kobo Aura HD. I ended up finishing Bunker Hill on that reader and toting it along on a number of business trips. It made the long plane rides and late nights in a hotel more bearable.