— Screen size: 7.9 inches diagonally

— Screen resolution: 1024 by 768 pixels, 162 pixels per inch

— Weight: 0.68 pound (0.69 pound for cellular versions)

— Cameras: 5-megapixel camera on back and a low-resolution camera on front, for videoconferencing

— Battery life: 10 hours

— Operating system: Apple’s iOS

Pros: Looks great. Unmatched access to third-party applications, high-quality Apple software and the iTunes store. Large screen. Available with access to fast 4G wireless broadband networks, starting at $459.

Cons: Data storage cannot be expanded with memory cards. Screen is of relatively low resolution.

Amazon.com Inc.’s Kindle Fire HD.

— Price: $199 with 16 gigabytes of storage, $249 with 32 GB

— Screen size: 7 inches diagonally

— Screen resolution: 1280 by 800 pixels, 216 pixels per inch

— Weight: 0.87 pound.

— Cameras: Front-facing camera.

— Battery life: 11 hours.

— Operating system: Modified version of Google’s Android

Pros: Cheap and portable. Convenient access to Amazon store. Speakers on either side of screen for good stereo effect.

Cons: Small selection of third-party applications available from Amazon. No rear camera for taking video and photos. Data storage cannot be expanded with memory cards.

Amazon.com Inc.’s regular Kindle Fire:

— Price: $159 with 8 gigabytes of storage

— Screen size: 7 inches diagonally

— Screen resolution: 1024 by 600 pixels, 170 pixels per inch

— Weight: 0.88 pounds

— Cameras: none

— Battery life: 8.5 hours.

— Operating system: Modified version of Google’s Android

Pros: Cheap and portable. Convenient access to Amazon store.

Cons: No-frills tablet lacks camera and microphone. Small selection of third-party applications available from Amazon. Data storage is small and cannot be expanded with memory cards. No option for cellular wireless broadband.

Barnes & Noble Inc.’s Nook HD

— Price: $199 with 8 gigabytes of storage, $229 with 16 GB

— Screen size: 7 inches diagonally

— Screen resolution: 1440 by 900 pixels, 242 pixels per inch

— Weight: 0.69 pound

— Cameras: None

— Battery life: Up to 10.5 hours of reading and up to 9 hours of video

— Operating system: Modified version of Google’s Android

Pros: Storage memory is expandable with microSD card. Sharpest screen. Light.

Cons: Selection of third-party applications is small. Lacks cameras and option for cellular broadband.

Google Inc.’s Nexus 7

— Price: $199 with 16 gigabytes of storage, $249 with 32 GB. Add $50 for 32 GB model with cellular capability.

— Screen size: 7 inches diagonally,

— Screen resolution: 1280 x 800 pixels, 216 pixels per inch

— Weight: 0.75 pounds

— Cameras: Front-facing, 1.2 megapixel camera

— Battery life: 10 hours

— Operating system: Google’s Android

Pros: Access to a wide variety of games, utilities and other software for Android devices, though not as extensive as apps available for iPad. Option for cellular wireless broadband.

Cons: Integrates with Google Play store, which is still new and isn’t as robust as Apple or Amazon’s stores. Data storage cannot be expanded with memory cards.