Tablets weren't on anyone's Christmas list three years ago; fast-forward to 2012, and there are literally tablets everywhere you look, with new ones continuing to roll out each month. 

With the very first iPad in 2010, Apple proved tablet computers could have mass market appeal; since then, it's been a dizzying race to the top, with companies releasing new devices once, twice or more each year. Apple continues to improve and expand its own iPad line-up, but dozens of competitors have since entered the tablet game, with Google, Samsung, Amazon, Barnes & Noble, and now even Microsoft leading the rest of the pack.

Starting a few months ago, each of these prominent companies debuted their tablet for the holiday season -- Google's new and improved Nexus 7, Samsung's Galaxy Tab 2, Amazon's Kindle Fire HD, Barnes & Noble's Nook HD, and the all-new Microsoft Surface. Apple also refreshed its tablet line-up once more in October with the fourth-generation iPad and all-new iPad Mini.

In 2012, companies focused on two key tablet sizes: The 7 inch tablet, and the 10 inch tablet. The iPad, Nexus 10 and Galaxy Tab 2 10.1 belong in the 10-inch category, while the Kindle Fire HD, Nook HD, Nexus 7, and iPad Mini all belong in that smaller 7-inch category -- the iPad Mini's actually more like 8 inches (7.9, to be exact), but the point is, these tablets can be held in one hand.

With 2012 in the rear-view mirror, we can finally grade these tablets against each other to determine the best slate in each major category. After much deliberation, here's what we came up with.

Best 10-inch Tablet: Fourth-generation iPad with Retina Display (a.k.a. "iPad 4")

This competition really wasn't too close. The iPad, the original landmark tablet, is still the gold standard for all 10-inch tablets.

This year, Apple released two 9.7-inch tablets -- one in March, and one in October. The third-generation iPad released in March was the first iPad to feature a Retina Display, and it was a beauty. The tablet had a few drawbacks -- that screen's a real power sucker, and heats up on occasion -- but the Retina Display and enhanced innards really made the iPad 3 into an incredible all-around experience. Read my full review of the device here.

The iPad 3 would've been enough for most companies in one year, but Apple wasn't done yet. When the company introduced its new Lightning connector-friendly iOS devices in September and October, including the iPhone 5 and iPad Mini, Apple chose to give the third-generation iPad a quick but important upgrade to its full-sized iPad.

The fourth-generation tablet looked just like Apple's third iteration, but its looks were deceiving; this iPad 4 was a true speed demon, and only further separated Apple from the rest of the pack when it comes to tablets.

Powered by the all-new A6X chip from Apple, the iPad 4 boasts double the chip speed and graphics performance of its predecessor, as well as new features like picture stabilization and face detection when snapping photos or shooting video.

The iPad 4 also features "ultra-fast" Wi-Fi that actually doubles the connection speed the iPad 3 had; for LTE customers, Apple also expanded the number of LTE frequencies supported by the iPad to include more carriers in Europe, Australia, and even here in the US, including Sprint-Nextel.

The iPad isn't a cheap device -- the iPad 4 sells at Apple's same price point of $499 for Wi-Fi-only and $529 for LTE -- but this is the best tablet experience you can possibly have in 2012. It's gorgeous, it's fast, and it's lightweight. The iPad Mini may become the more popular iPad over time, but in 2012, the iPad 4 was king.

Best 7-Inch Tablet: First-generation iPad Mini

This decision was not so easy. There are far more 7-inch tablets available on the market today than 10-inch tablets, and these smaller models have many more variables to consider. Weight. Feel. Display. Value. 

The Nexus 7 may have the best features and ecosystem at the low $199 price point, but if you're looking at the very best 7-inch tablets, regarding both price and the total package, you gotta go with the iPad Mini.

Now, if you know me or you've read anything I've written over the last few months, you know what I think of the iPad Mini. I'm not a huge fan. (Need a quick primer? Read my scathing review, or the iPad Mini listing atop my "Biggest Disappointments of 2012" list.)

The iPad Mini suffers because it has no Retina Display, and that sucks because it only costs about $100 less than the full-sized iPad with a Retina Display. Many smart people may opt to shell out the extra bucks for the full-sized iPad with the real deal display, but there are reasons for buying an iPad Mini I haven't mentioned yet.

The iPad Mini shines in three particular areas: portability, battery life, and FaceTime. 

It's comfortable and incredibly easy to both hold and use with one hand -- much like an iPhone in this way, and that'll only get easier when the device gets thinner in the future -- but the iPad Mini is also very, very light. It's roughly the weight of a thick notepad, so it's light, but not so much that it feels plasticky.

Even though the iPad Mini's screen is a major bummer -- that same 1024 x 768 resolution from the iPad 2 days -- the lack of a Retina Display means extended battery life for true all-day usage. At 12+ hours of reported battery life, the first-generation iPad Mini is a major accomplishment for Apple.

And finally, for FaceTime users, Apple's decision to build a FaceTime HD camera instead of a simple VGA camera makes perfect sense. This tablet is so easy to hold and pick up, and considering the growing use of video chatting and conferencing, Apple was wise to focus on this particular feature and really make it shine.

These features are great, but other tablets can boast similar specs; where the iPad Mini shines is its experience. The tablet is powered by iOS 6, which is by far the best operating system on any mobile device in 2012 hands-down.

I've played with every tablet, including the Nook, the Kindle Fire, the Nexus 7 and beyond. Their interfaces are pleasing to look at, but the compliments more or less end there. The interfaces, while attractive, have varying levels of difficulty, but all lack the intuition of iOS. From a functionality standpoint, these tablets are often slow and buggy, but it's their limited ecosystems that really make these tablets less fun than the iPad.

The iPad, in whichever form you find it in -- full-sized or mini, is powerful for its functionality, its beauty, but also its expansive ecosystem of applications.

Google and Amazon have large ecosystems of their own, but their ecosystems have yet to translate to native applications within a grander marketplace, which only Apple has been able to accomplish. There are plenty of Android developers building applications for the Google Play store -- and most of today's tablets not named iPad are powered by Android -- but the ecosystem is completely insecure and not yet as organized as Apple's App Stores.

The iPad Mini may not be as beautiful or glorious a tablet as its older brother, but it's still better than all of the other 7-inch tablets on the market today. Its screen ain't all that, but Apple compensates with speed, battery life, great performance, and the best interface and ecosystem money can buy.

The iPad Mini isn't as cheap as its competitors -- in fact, it's more than $120 more than the vast majority of Apple's rivals, which sell their 7-inch tablets around $200 -- but if you need an ultra-portable tablet right now (you really can't wait another 6 months for the sequel?), the iPad Mini is the best 7-inch tablet money can buy.