When buying a tablet, the first step is to decide on the size you want. They fall into two rough categories: the full-sized tablet, pioneered by the iPad, and the half-size tablet, epitomized by the Kindle Fire.

If you’ve settled on a small tablet, here are some top choices.

Apple iPad Mini (starts at $329 for 16 gigabytes of storage)

The most expensive of the small tablets is also the prettiest. Its exquisitely machined metal rim sets it well apart from competing tablets clothed in plastic and rubber. It’s also thin and light, despite having a screen that’s 40 percent bigger than other “small” tablets.

But the quality of the screen doesn’t quite measure up to the competition. It has fewer pixels than other small tablets, and they’re spread over a larger area, making for a relatively coarse, pixelated look. On the other hand, the Mini has two cameras, front and back, which is a rarity.

Where the Mini really wins is in third-party apps: It’s the only small tablet that has access to Apple’s App Store, with a superlative selection of high-quality apps. It’s an excellent addition to the household that’s already hooked on iPhones and full-size iPads. For those not wedded to the “Apple system,” the other tablets merit a close look.

Amazon Kindle Fire HD (starts at $199 for 16 gigabytes of storage)

A year ago, the Kindle Fire was the plucky, cut-rate tablet, the Dodge Neon to the iPad’s BMW. This year, the gap in quality and features has narrowed considerably. The Kindle Fire HD has a better screen than the iPad Mini, and now sports a front-facing camera. The original Kindle Fire had none.

In another nice touch, it has speakers on either side of the screen when it’s held horizontally, making for much better stereo sound when you’re playing a movie.

The selection of content is narrower than for the iPad, since it’s heavily slanted toward Amazon’s services. Likewise, the selection of third-party apps is smaller than on the iPad or Google’s Nexus 7. But there are enough games to thrill a kid for hours, and like Barnes & Noble’s Nook, the Kindle can be configured with a special “kid mode” that shields them from racier content – and from messing up your settings.

The Kindle Fire is especially useful for members of Amazon’s Prime shipping service, since they get access to free streaming movies. On the other hand, anyone could be annoyed by the ads that appear on the lock screen. Getting rid of them costs $15. There’s no option for cellular broadband, so you’re limited to Wi-Fi connections.

Barnes & Noble Nook HD (starts at $199 for 8 gigabytes of storage)

Barnes & Noble has paid a lot of attention to the screens on its Nooks. This year, it’s clearly outdone the competition, with a screen that packs the pixels tighter than any other small tablet. It’s very sharp and colorful, approaching the look of the Retina screen that graces the full-size iPad.

The other strength of the Nook HD is that it has a slot for a memory card, meaning that you can expand the storage space for movies and music by 32 gigabytes for $25. It’s the only tablet in our roundup with this feature.

The downside is that the Nook HD is less of a general-purpose tablet and more of a consumption device for books and movies. It doesn’t have a camera, so it’s no good for videoconferencing. The selection of apps is the smallest. You’ll find big names like “Angry Birds” here, but there is no depth to the catalog. There’s also no option for cellular broadband.

Still, the Nook is an excellent choice for avid readers, kids and others who won’t be frustrated by the small selection of things like 3-D shoot-em-up games.

Google Nexus 7 (starts at $199 for 16 gigabytes of storage)

Google this year launched the first tablet under its own brand – frustrated that Amazon and Barnes & Noble were taking Google’s Android software, gutting it and using it to power tablets that don’t yield the search giant a red cent.

The Nexus 7 has a powerhouse processor and a screen similar to that of the Kindle Fire HD. Since it runs stock Android, it has access to hundreds of thousands of applications written for Android smartphones, and it has more sophisticated multitasking abilities than the competitors, so it’s easy to switch from program to program. Like the iPad Mini, it has a GPS chip for navigation. It has a front-facing camera for videoconferencing.

There’s a $299, 32-gigabyte version that can connect to AT&T’s wireless network.

The Nexus 7 is a great tablet for the technophile who would chafe at the restrictions imposed by competing manufacturers. But anyone will be able to appreciate it. In terms of kid-friendliness, it’s beaten by Amazon and Barnes & Noble.