Tablet computers are in high demand -- from Apple's popular iPad and much-rumored iPad mini, to Google's smaller but powerful Nexus 7 and Microsoft's forthcoming Surface.

But as the popularity of the Kindle Fire proves, tablets are not one-size-fits-all. For business users, your choice can depend on how you plan to use a tablet -- making presentations, processing transactions or reading documents. You should also take into account your preferred mobile operating system, available apps and the kind of connectivity you'll need.

Here's our guide to eight of the best existing and soon-to-arrive tablets:

Apple iPad: 3rd generation

In March, Apple launched the third-generation iPad, notable mainly for its high-resolution Retina display, more powerful five-megapixel camera and optional 4G wireless network connectivity.

Pros: Several iOS business apps have versions designed specifically for the iPad, including task-management tool OmniFocus and Microsoft Office.

Cons: But many iOS apps for services popular with small-business users, such as Freshbooks and GoToMeeting, are still designed only with the iPhone in mind. This means using such apps on an iPad is like having a giant iPhone, and many iPad users find them unwieldy.

Price: From $499 (16 GB, Wi-Fi only) to $830 (64GB and 4G with AT&T or Verizon service). As with any tablet, you either have to pay for a new tablet data plan or add the device to an existing plan. Price vary depending on the carrier.

Related: With a Dazzling Display, the New iPad Will Be Attractive for Many Business Owners

Nexus 7

Manufactured for Google (Android) by Asus, the Nexus 7 tablet, was introduced in the U.S. this summer. It has a display measuring only 7 inches diagonally, compared to the 9.7-inch iPad display.

Pros: Smaller tablets fit more comfortably into pockets or purses and tend to be more convenient to hold with one hand. So far, the Nexus 7 is the only tablet sporting the latest version of the Android operating system, called "Jellybean." It will be among the first to receive Android system updates pushed directly from Google and not from wireless carriers or device manufacturers.

Cons: So far, the Nexus 7 is Wi-Fi only, and the maximum available storage is 16 GB. There isn't a sizable selection of Android apps optimized for this device yet. But because it's a relatively small tablet, using apps designed for Android smartphones may be acceptable.

Price: $199 (8GB) or $249 (16GB).

Related: Google's Nexus 7: The Latest Entry in the Tablet Wars

Samsung Galaxy Tab models

One of the first Android tablets to hit the market, the Galaxy Tab was released in the U.S. in late 2010. Currently, there are three main products in the Galaxy Tab family.

Pros: On the large side, Samsung's full-size Galaxy Note tablet features a 10.1-inch display and comes with an "S-Pen" stylus option, which can be useful if you sometimes prefer writing or drawing on your tablet in a paper-like fashion.

If you prefer a smaller tablet or 4G wireless connectivity, Samsung offers the seven-inch Galaxy Tab 7.0 and it's counterpart, the 7.0 Plus. In between, size-wise, is the Galaxy Tab 7.7.

Cons: Galaxy Tab products come with the "Ice Cream Sandwich" version of Android, as modified by Samsung. This means that updates to Jellybean and future Android "flavors" will lag behind Nexus tablets, perhaps by many months

Also, all 10.1-inch Samsung Galaxy tablet models are Wi-Fi only.

Prices: The Galaxy Note tablet ranges from $499 (16GB) to $549 (32GB). The 10.1-inch version of Samsung's Galaxy Tab 2 starts at $399 (16GB). The Galaxy Tab 7.0 and 7.0 Plus cost about $250 (16GB, 4G) from carriers. The Wi-Fi only models cost up to $100 more. The Galaxy Tab 7.7 is available only from Verizon, so it includes 4G access, and starts at $279 (16GB).

Related: What the Apple vs. Samsung Lawsuit Means for the Future of Smartphone Design

Samsung Galaxy Note hybrid phone/tablet

If you'd rather not carry two mobile devices, this hybrid phone/tablet may be right for your business. Samsung launched the Galaxy Note a year ago.

Pros: It's like two mobile devices consolidated into one. Also, it features Samsung's S-Pen stylus, which reviewers have praised for its precision and responsiveness. And it includes an eight-megapixel front-facing camera.

Cons: At 5.3 inches, the display is large for a phone, but small for a tablet. Some users find this awkward. The Galaxy Note may come with Android Ice Cream Sandwich installed but, depending on carrier or retailer inventory, some devices may be shipped running Gingerbread -- a much older version of Android.

Price: Available in the U.S. via AT&T starting at $199 (with a two-year service contract) or $599 (no contract), or from T-Mobile starting at $249 with a two-year contract or $699 (no contract).

Related: 5 Procrastination-Busting Smartphone Strategies

Asus Transformer Pad Infinity

The Asus Transformer Pad Infinity features a high-resolution 10.1-inch display and up to 64 GB of memory, and it comes with Android Ice Cream Sandwich.

Pros: Reviewers generally praise this tablet's built-in keyboard dock. It effectively turns this tablet into an Android-powered laptop (with a full keyboard, track pad and USB port) and contains its own battery, providing up to seven additional hours of use.

Cons: This tablet is Wi-Fi and Bluetooth only.

Price: About $480 (32GB) and $580 (64 GB).

Related: 5 Things to Consider Before Buying a Smartphone or Tablet for Business
 

Microsoft Surface tablets

Reportedly going on sale Oct. 26, the Surface represents Microsoft's first serious foray into the tablet market.

Pros: According to Microsoft, these tablets will feature the new Windows 8 operating system designed to run on both computers and mobile devices.

The base Surface model will run a slightly modified version of this operating system (Windows RT) and will be available in 32 and 64 GB versions. The Surface Pro will run straight Windows 8 and come in 64 and 128 GB versions.

They also will feature a 10.6-inch HD display and a molded magnesium casing, which could make them look and feel sleeker than most Android tablets.

Cons: Windows 8 features a new tile-based user interface called "Metro." Users who are accustomed to previous versions of Windows may find it perplexing. Windows apps will need to be radically redesigned to accommodate this operating system, and will probably require further optimization for the Surface.

Price: Microsoft CEO Steve Ballmer has hinted that prices could range from $300 to $800.

Related: For Windows Users, Microsoft's 'Surface' Might Be Your Next Tablet
 

HP ElitePad

Microsoft won't be the only company selling Windows 8 tablets. In January, HP expects to launch its ElitePad, a 10.1-inch tablet intended primarily for business users.

Pros: It will come running the Windows 8 operating system, but reportedly it also will be able to run Windows 7 or XP. Up to 64 GB of storage will be available.

This device is meant to be durable, with a more rugged casing than most tablets have. It also comes with security software installed. Accessories will include a jacket with extra battery, stylus and docking station.

Cons: It will face the same issues with the new Windows 8 user interface as the Microsoft tablet. Its security measures and some other features may be overkill for most small-business users.

Price: Not announced yet, but expect the ElitePad to be costlier than most comparable tablets.

Related: 4 Tools for Turning an iPad into a Retail Workhorse

Apple iPad mini

Apple is expected to announce a smaller and less expensive iPad model as early as Oct. 23.

Pros: In September, leaked images of a purported iPad mini showed a 7.85-inch display, compared to the 9.7-inch display on the standard iPad. At this size, iPhone apps that are unwieldy to use on a full-size iPad may seem better.

The iPad mini would probably offer 3G or 4G network access, in addition to Wi-Fi.

Cons: Apple will need to keep the price range for this product competitively low, and that will entail tradeoffs. Unlike the standard iPad, an iPad mini would be unlikely to have a Retina display. And the base model may come with only 8GB of memory.

Price: If rumors prove true, the iPad mini will most likely be priced to be competitive with Amazon's Kindle Fire HD, which starts at $199.

Related: Everything You Need to Know About Apple's Upcoming iPad Mini
Related: Forget the iPhone 5. Apple's iPad Mini Might Be Better for Business