Altogether, 2014 was an unremarkable year for tablets. Demand rose, but to a much lesser extent compared to prior years -- according to research firm IDC, the tablet market expanded just 7.2% this year.

Consumers opting for larger phones may find themselves using their tablets less and less. Others may find that their older tablets, purchased several years ago, are still able to accomplish most tasks. But if you're in the market for a new tablet, one that should perform well over the course of the upcoming year, there are several devices to choose from.

Small tablets

Winner: Nexus 7
There are plenty of small tablets; unfortunately, most of them are not worth owning. As a throwaway device, there are innumerable 7-inch tablets in the $50-$130 range, but buyers seeking a small tablet should opt for Google's (GOOG -1.10%) (GOOGL -1.23%) slightly more expensive ($180),  second generation Nexus 7.

At this point, it's nearly a year and a half old -- practically an eternity for mobile tech -- but it holds up. Its processor is a bit dated, but its screen is competitive with current flagships. As a Nexus device, Google remains committed to updating its operating system -- Android 5.0, the latest version of Google's mobile operating system, has begun rolling out to Nexus 7 owners. Few, if any, other Android tablets released in 2013 are likely to get the update.

Mid-size tablets

Honorable mention: Nvidia Shield
NVIDIA's (NVDA -10.01%) Shield Tablet is a device aimed primarily at PC gamers. In particular, those with a newer model NVIDIA graphics card installed in their gaming PC.

Using NVIDIA's proprietary software, gamers can stream games from their PCs to the Shield tablet over a wireless network. Paired with NVIDIA's Shield controller, and an HDMI cable, the Shield tablet can work as a makeshift gaming console, beaming games played on an office PC to a living room television. In addition, the Shield tablet can also play Android games, and a handful of cloud-based games streamed from Nvidia's Grid service.

But even if you have no interest in gaming, the Shield is a fairly solid Android tablet, with an 8-inch, HD display, speedy processor, included stylus, and front-facing speakers. Unfortunately, battery life is unremarkable, but at $299, it's an attractive tablet.

Runner-up: Galaxy Tab S 8.4
Samsung
's (NASDAQOTH: SSNLF) Galaxy Tab S 8.4 has one of the best displays on any tablet, with an ultra-high resolution screen that's sharper (359 pixels per inch) than any other tablet. It's also, at 8.4-inches, larger than most other mid-size tablets.

Like other Galaxy Tabs, the S 8.4 doesn't come with Samsung's S-Pen, or any other exclusive features. In fact, it's basically just a blown-up version of Samsung's Galaxy S5 smartphone. But at less than $400, that's not a bad thing.

Winner: iPad Mini 2
Apple
's (AAPL -1.22%) iPad Mini 2 was introduced in late 2013. Yet, a year later, it remains the premiere mid-size tablet. Like the full-size iPad, the Mini bests its rivals in terms of software, offering more tablet apps than the competition.

Apple has released a follow up to the iPad Mini 2, but the third generation is not worth the asking price.The iPad Mini 3 has the same screen, camera and processor as the 2 -- it differs only in its inclusion of TouchID. Unless you're dead set on having a fingerprint scanner, mid-size tablet buyers should opt for the $349, 32 GB iPad Mini 2.

Large tablets

Honorable mention: Samsung Galaxy Note Pro 12.2
In terms of screen real estate, Samsung's Galaxy Note Pro 12.2 can't be beat: The device is massive, with an enormous, 12.2-inch, ultra-high definition display. That makes it more of a laptop alternative than a true tablet, which is either a good or bad thing depending on how you plan to use the device.

Like Samsung's other devices, it's powered by Google's Android, but overlaid with the TouchWiz skin. Notably, it's equipped with Samsung's S-Pen, the smart stylus that defines Samsung's Note series. Unfortunately, the Galaxy Note Pro 12.2 is the most expensive tablet on this list, retailing for around $600.

Runner-up: Nexus 9
Google's Nexus 9 is sort of a tweener, bigger than most mid-size tablets, but relatively small for a large tablet. Still, it's among the best Android tablets in its class, with a high-end, almost desktop-class processor, and a pure, stock version of Android.

Starting at $399, Google's Nexus 9 is relatively inexpensive for both its size and its specs. If it has a weakness, it's the Android operating system itself: Compared to iOS, Android has fewer tablet-optimized apps and games.

Winner: iPad Air 2
Apple's iPad Air 2 is $100 more expensive than the Nexus 9, but is worth the premium. The iPad Air 2 is the best iPad ever made, and the best tablet overall.

Hardware wise, it features Apple's latest mobile processor (the A8X), a 9.7-inch, HD display, and TouchID. Where the iPad Air 2 really excels, though, is the software -- despite the iPad's dwindling market share, Apple's tablets continue to get the bulk of attention from mobile developers. If you want the premiere large tablet experience, Apple's flagship tablet remains the best in its class.