The world of tablets keeps growing. New entries include the Nook HD and HD-plus, the iPad Mini, and the Surface - Microsoft's first tablet.

Consumer Reports tests to find the best. While the top ones all have something to offer, there are big differences.

For example, the $500 Surface has a superb 10-inch screen plus a handy stand, and you can get a cover with a built-in keyboard. However, when it comes to content, Microsoft has a way to go.

Paul Reynolds with Consumer Reports says, "Windows tablets lack access to the big content selection from Apple or the Android Marketplace, or even the Amazon and Barnes and Noble content offerings."

Size is another important consideration - the 7-point-8-inch i-Pad Mini is Apple's first smaller tablet, competing with other small tablets like the Barnes and Noble Nook HD and Kindle Fire HD from Amazon.

Consumer Reports finds in many ways the Mini is every bit as good as the bigger i-Pads. The screen offers crisp text, optimal photo viewing, and good sound.

The $330 i-Pad Mini is also light, making it extra portable.

But for $200, the Barnes and Noble Nook HD is well worth considering. Sharp text that fills the 7-inch screen makes reading a pleasure.

However, the larger 9-inch Nook H-D-plus is a better choice if you're a magazine lover. It starts at $270.

Paul believes, "The iPad still offers the most content, and its screen's a little bigger than the Nook HD+. But at $500 and up, it costs almost twice as much."

Consumer Reports says no matter what your priorities are, there's never been a better selection of tablets to choose from.

If you're thinking about buying an extended warranty for a tablet, Consumer Reports says it may not be worth the money.

A recent survey found only 4% of tablet owners needed repairs.

But if you still want to get one, Consumer Reports says consider less expensive coverage, such as the $28, two-year accidental plan sold at Walmart.