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Whether your home is crowded with too many books or you simply want to digitize your library to take with you on vacation, now’s a great time to invest in an e-reader for your at-home and on-the-go reading pleasure. The displays are optimized for reading, and without the distractions of messaging, games and video, you’ll get a more immersive reading experience. Over the past month we’ve tested nine e-reader models, and these two stood out above the rest:

Best overall e-reader

With access to Amazon's vast library, a display that's adjustable enough to let you read without fatigue in almost any light, easy-to-use controls and a comfortable design, the Kindle Oasis is the best e-reader we've tested.

Best budget e-reader

The Kindle Paperwhite gives you most of what the Oasis offers, with a smaller, simpler, but still very readable display, at an affordable price.

Best overall e-reader: Kindle Oasis ($249.99; amazon.com)

Kindle Oasis
Amazon
Kindle Oasis

Simply put, the Kindle Oasis is a dream to read on. We returned to it over and over in our testing due to its comfortable feel in the hand, well-placed page-turn buttons and multiple brightness and color temperature settings that let us read easily in different settings. Thanks to the Oasis’$2 1-inch-thick bezel, your hand has a place to rest and it won’t accidentally brush up against the touch screen — a problem we had with other e-readers we tested. Its square design is also comfortable enough to hold one-handed for hours at a time. (Seriously, our hand never felt tired holding this thing.)

While you don’t technically need an Amazon account to use the Kindle Oasis, you’ll probably want to register in order to have access to the millions of Kindle books available from the Kindle library. Upon setup of the e-reader, you’ll be asked to sign in with your Amazon account if you have one and connect to Wi-Fi, all of which can be done in just about a minute. From there, you’ll then be able to search for books directly from the device itself. Amazon Prime subscribers will have access to Prime Reading, which includes around 1,000 free titles that rotate on a periodic basis, but you can also register for Kindle Unlimited ($9.99 per month), a separate subscription that gives you access to over a million books and audiobooks. If you’re not an Amazon Prime or Kindle Unlimited subscriber, you can still purchase books on an individual basis from the Kindle store. We were able to easily find every book we searched for, even brand-new releases on their publication date.

Kindle readers don’t directly support Overdrive, a free service that allows you to borrow books using your library card. However, you can easily check out e-books via Overdrive on your computer or the Overdrive app on your tablet or phone and read them on the Kindle — just follow these instructions. We had no issue checking out and returning books after setting up an Overdrive account with our library card. You can also read MOBI files and PDFs on your Kindle by emailing them to the device itself, and EPUB files by converting them to MOBI files using free online software. The Kobo readers do let you check out books directly from Overdrive, making them a good choice if that’s your primary interest in an e-reader (though we prefer the Kindles enough that we generally think it’s worth the slight inconvenience of borrowing from another device).

One of our favorite features of the Oasis is its warmth brightness setting, a feature not found on the other Kindles we tested. In addition to being able to adjust the display brightness, we were also able to adjust the color temperature of the light, filtering out blue light that could negatively affect your eyes at night. It may seem like a small addition, but it went a long way in helping our eyes adjust to the light. If you’re reading in bed while a partner is trying to sleep, it’s also a great way to minimize disturbing them.

The 7-inch E Ink Carta screen on the Oasis is both waterproof and glare-free. We took the e-reader out under the sun, on a train and poolside and had no issues being able to read the text on the screen. We even dunked it in the pool and took it out in the rain with no issue. There are also a plethora of ways to customize your reading experience on the Oasis, including 14 font size settings, five boldness settings, nine fonts (including one to help those with dyslexia), two orientations, three margin settings, two alignment settings and three spacing settings, not to mention the ability to highlight favorite passages and connect your Goodreads account.

Because the Oasis has Bluetooth connectivity, you’ll also be able to pair wireless headphones to the device and listen to audiobooks through it. It took us just seconds to connect our pair of Pixel Buds to the Oasis and start listening.

Finally, the battery on the Oasis charges from 0% to 100% in just an hour, and it will last an estimated 50 hours with brightness set to 12 and Airplane Mode turned on. That’s the best battery life of all the e-readers we tested and should last the regular reader weeks even if they read for an hour every night.

Best budget e-reader: Kindle Paperwhite ($129.99; amazon.com)

Daniel Toy/CNN

The Kindle Paperwhite is a great e-reader that should suit any person on a budget. It features the same accessibility features, waterproofness and touch-screen capabilities as our top pick, but it lacks the Oasis’ page-turn buttons and has a slightly smaller E Ink Carta screen at 6 inches. It’s an extremely portable device that rose above the competition due to its extensive library, comfort in the hand and ideal screen size. It also felt better made and more comfortable than the more plasticky Kobos. It charged to 100% battery from 0% in two hours and lasted for weeks in our testing.

How we tested

We spent hours reading a multitude of books on each e-reader over the course of a month, noting special features like waterproofness in addition to accessibility features, ease of navigation of the user interface, overall design, screen size, library support and battery. Below are the criteria we used to judge each e-reader:

Platform/library support: We noted the library size of each e-reader as well as the file formats that are possible to read on them and how easy those file formats are to transfer.

Screen: We looked at the overall quality and responsiveness of each e-reader’s screen, using touch controls to shop for books, navigate the UI and flip pages. Is it glossy and smooth or matte and scratchy? We also tested glare by bringing each e-reader outside in the sun.

Software/user interface/performance: We noted how intuitive the user interface is and what accessibility features are built in.

Design: How comfortable is each e-reader’s design? Does it rest easily and comfortably in your hand for prolonged periods of time? Does it feel sturdy, or is it plasticky and cheap?

Battery: We used a 5-watt USB power adapter and the cord included with each e-reader to charge each device, monitoring how long it took each e-reader to charge from 0% to 100%. We then read for an hour per night on each device with brightness set to 12 and Airplane Mode turned on, noting the battery percentage drop over time.

Warranty: We looked at how long the included warranty is for each device and what it covers. Every e-reader we tested included a one-year warranty, resulting in a nine-way tie in this category.

Other e-readers we tested

Kindle ($89.99; amazon.com)

Kindle
Amazon
Kindle

The original Kindle e-reader is a decent device, but we noticed slower buffering times, a decreased battery life and blurry cover images while testing it. We’d suggest springing for our budget pick in the Paperwhite for its waterproofness (which the Kindle lacks) and better resolution.

Kindle Kids ($109.99; amazon.com)

Kindle Kids
Amazon
Kindle Kids

If you’re looking for an e-reader for younger bookworms, look no further than the Kindle Kids Edition. It boasts an easy-to-use interface and a multitude of parental control settings so you can make sure your child or children won’t get into anything they shouldn’t. It also comes with a colorful case to protect the device. However, note that this e-reader is not waterproof, so if you have a particularly messy kid, it could break if not properly taken care of.

Kobo Forma ($249.99; walmart.com)

Kobo Forma
Walmart
Kobo Forma

The Kobo Forma is similar in design to the Kindle Oasis, with two page-turn buttons on a bezel and a large screen. However, the buttons feel cheap and are hard to press, while the 8-inch screen is almost too large to read on comfortably. It’s also 0.3 ounces heavier than the Oasis, which doesn’t seem like a lot but coupled with the larger size makes it slightly less comfortable to hold for extended periods of time.

Kobo Libra H2O ($169.96; walmart.com)

Kobo Libra H2O
Walmart
Kobo Libra H2O

The Kobo Libra H2O is our pick for favorite Kobo reader, so if you want a device specifically to search for and borrow books from the library via Overdrive, this may be the e-reader for you. Its design is reminiscent of the Forma above, but its 7-inch screen is better suited to reading at length. Also, as its name suggests, it’s completely waterproof; however, the Kobo Libra H2O lost points due to its plastic feel and hard-to-press page-turn buttons that aren’t as comfortable as the ones on the Oasis.

Kobo Clara HD ($115.21; walmart.com)

Kobo Clara HD
Walmart
Kobo Clara HD

We really liked the crisp HD screen on the Kobo Clara HD, which looks great both indoors and outdoors. We also appreciated the multiple brightness settings that allow you to filter out blue light and bring in what it calls “natural light.” Overall, however, we preferred the Kindle Paperwhite for its comfort, ease of use and battery.

Kobo Nia ($99.99; walmart.com)

Kobo Nia
Walmart
Kobo Nia

The Kobo Nia is a no-frills e-reader that’s similar to the original Kindle. It boasts a 6-inch screen that feels a little small, and its battery life was weaker than the competition. We preferred the screen on the Kobo Clara HD for those interested in a Kobo over a Kindle device.

Nook GlowLight 3 ($119.99; barnesandnoble.com)

Nook GlowLight 3
Barnes & Noble
Nook GlowLight 3

The Nook GlowLight 3 was the least favorite e-reader that we tested, with a cheap-feeling design and extremely slow response speeds. The buffering of pages alone made this a frustrating e-reader to use, and we found the Kindle and Kobo libraries to be cheaper and more robust than what Barnes & Noble offers.

Read more from CNN Underscored’s hands-on testing: