It seems there is a keyboard released for the iPad every few weeks, and figuring out which one might work best is almost as hard as finding a good app in the App Store.

This collection of iPad keyboards is unique in that with the exception of one, they all have been used by me. I own all of them, except two that were supplied for evaluation by the manufacturer. I have used all but one of these keyboards extensively in my work, and I have a good feel for which ones are best for me.

All of the keyboards in this collection are shown closed for thinness and open for business. With the one exception mentioned, all of the keyboards charge via microUSB and will last for months on a charge. A microUSB to USB charging cable is included with these keyboards. They all connect to the iPad via Bluetooth.

In addition to the eight good iPad keyboards, there is a bonus for iPad mini owners. Three keyboards for the iPad mini are also covered in this collection.

This new case from Belkin uses innovative magnetic strips to provide three different viewing angles for using the iPad with the keyboard. The Bluetooth keyboard turns on automatically when the iPad is placed in one of the strips and turns off when the magnetic connection is broken.

Dimensions: 245x197x18.8mm (9.6x7.75x0.74 inches); 411g (0.9 pounds)

The Belkin Ultimate Keyboard Case for the iPad is available in black and in white. The white model, which is aluminum on both the top and bottom of the case, is $129. The white model should be slightly lighter than the black one.

$99.99 from Belkin

This case allows sliding the iPad forward, covering the keyboard for use as a tablet. This mode works surprisingly well in spite of the extra weight of the case.

This case has just been released and I have not used it. It is worth including in this collection given the history of Logitech with good accessories and the use of magnets for propping the iPad at convenient viewing angles, much like the Belkin model.

Logitech has designed the Folio with a full keyboard that works much like the others in this roundup.

Dimensions: 248x198x25mm (9.76x7.8x0.98 inches); 639g (1.43 pounds)

$99.99 from Logitech

Logitech also makes the Keyboard Folio case in a version to work with the iPad mini.

$89.99 from Logitech

ZAGG has been making keyboards for the iPad as long as any company, and the Profolio+ is the latest model. It is also the best one I have used.

This keyboard is also a full case for the iPad, offering total protection for the tablet. It has a faux leather cover that makes it secure to hold. It is the thinnest folio from ZAGG to date and has the same good keyboard as the others.

The keyboard is thinner than the older models and is not only backlit but also offers seven colors of backlighting. The colors can be changed at will and each has three brightnesses to adjust to taste.

The Profolio+ is currently my favorite keyboard for the iPad.

Dimensions: 7.5x9.75x0.81 inches; 1 pound

See the full review by James Kendrick on ZDNet .

$129.99 from ZAGG

Like all of the keyboards covered, the Profolio+ is almost full sized and provides a great typing experience. Even the fastest touch typists should be able to use this keyboard without compromise.

The case uses magnets to turn the iPad on/off when the case is opened/closed. Magnets also hold the case closed when not in use.

The backlighting on the keyboard may sound like a gimmick, but it comes in handy quite often in my use.

Those who prefer a laptop form will really like the ClamCase Pro. Once the iPad is popped into the lid (an easy process) it becomes a MacBook Air-like laptop without a trackpad. Magnets in the ClamCase turn the iPad on and off when opened and closed.

The typing experience on the ClamCase Pro is the best of all the keyboards in this collection. It is also the most expensive of the lot.

The screen can be folded under the keyboard for using the iPad as a tablet without removing it. The keys are exposed to the hand holding the unit, which feels a bit weird. They are deactivated so there are no inadvertent keypresses when using the iPad this way.

Dimensions: 7.88x9.68x0.85 inches; 1.5 pounds

See the full review by James Kendrick on ZDNet .

$169 from ClamCase

The iPad fits securely in the lid of the ClamCase Pro and is very much like a laptop in use. The keys have a nice tactile feedback with good key travel.

Apple doesn't support trackpads with the iPad so it's no surprise it is missing on the ClamCase Pro. The space where a laptop trackpad would normally be found instead is a good palm rest on the front of the keyboard.

ClamCase Pro (left); ZAGG Profolio+ (right)

0.85 inches vs. 0.81 inches.

Those wanting a keyboard/case for the iPad that is the thinnest and lightest possible should look no further than the Ultrathin Keyboard Cover. The iPad snaps onto the keyboard via a magnetic hinge that closes like a book when not in use.

Magnets in the Ultrathin turn the iPad on/off when opened/closed. To use the keyboard, the iPad must be detached from the Ultrathin and popped into the keyboard slot. This slot also has magnets that firmly grip the iPad once it is in place. It is so secure that the whole assembly can be picked up by the iPad without detaching.

The Ultrathin only covers the screen of the iPad, so it offers no protection to the back.

Dimensions: 7.47x9.5x0.39 inches (without iPad); 0.78 pounds

Don't miss the video review by James Kendrick on ZDNet.

$99.99 in white, black, and red from Logitech

The Ultrathin keyboard offers a good typing experience for even the fastest typist. The key layout is standard and it has a row of special iPad control keys, as is standard on all of the keyboards in this collection.

Thickness comparison

ZAGG Profolio+ (left); Logitech Ultrathin Keyboard Cover (right)

0.81 inches vs. 0.39 inches (without iPad)

The Solar Keyboard Folio has several unique features not found on any of the other keyboards in this collection. This case is a real portfolio that closes like a book. It also uses two small solar panels to keep the keyboard charged, so it requires no charging by the user. Last but not least, it supports two different usage modes.

The solar charging keeps the keyboard charged even in room lighting. The solar panels are on one side of the folio, so you have to make sure these are exposed when the case is closed. Sadly, these panels are covered when being used as a keyboard so it can't charge while typing.

In addition to a typing position, the case supports a media viewing mode that puts the iPad at a comfortable angle for such activity. This position is also good for reading ebooks, in my experience.

Dimensions: 16.85x9.9x0.7 inches; 1 pound (without iPad)

Don't miss the full review by James Kendrick on ZDNet.

$129.99 from Logitech

The rubberized keys provide a pleasant and fast typing experience. The row of iPad control keys is present.

The case senses when the iPad is in the typing position and activates automatically.

When the iPad is placed in the forward position, as demonstrated in the photo, the keyboard enters into a media-playing mode. The one row of keys exposed below the iPad become special control keys for playing media.

This position is perfect for watching video on crowded airplanes.

ZAGG Profolio+ (left) vs. Logitech Solar Keyboard Folio (right)

0.81 inches vs. 0.70 inches

The original ZAGGfolio is not as good as the newer Profolio+, but it is still a good keyboard for the iPad. It works much the same as the newer keyboard, but without the backlighting. It is also a bit thicker and heavier, but is now available at a bargain price.

Unlike the Profolio+, the keyboard unit of the ZAGGfolio can be removed from the case and used by itself.

Dimensions: 7.6x9.75x0.9 inches; 1.1 pounds (without iPad)

Catch the full review by James Kendrick on ZDNet .

$49.99 from ZAGG

The keyboard of the ZAGGfolio is very similar to that of the Profolio+ with the exception of the backlighting. It offers a good touch typing experience and is a solid case for the very low price now available.

Thickness comparison

ZAGG Profolio+ (left) vs. ZAGGfolio (right)

0.71 inches vs. 0.90 inches

Those wanting a separate keyboard for the iPad will find the ZAGGkeys Flex to be an outstanding choice. The keyboard is slightly bigger than the other keyboards in this collection, and is very close to the size of a standard keyboard.

The black carrying case of the Flex opens to become a stand for the iPad. The separate keyboard means it can be positioned wherever the user prefers for typing.

Since this is a separate keyboard it can also be used with the iPad mini.

Android tablet owners may want to give the Flex a look as it can be used with those tablets, too. There is a toggle to turn the row of special control keys into keys for Android tablets.

Dimensions: 9.4x5.0x0.75 inches; 11.3 ounces

Full review by James Kendrick on ZDNet .

$79.99 from ZAGG

The separate keyboard and stand means the iPad can be used in portrait mode with the keyboard.

The ZAGG Mini 9 may look like the Profolio+, but this one has a big difference. It is a keyboard and case for the iPad mini. It has the same size keyboard as the iPad keyboards, so it provides a good typing experience. Unlike the other ZAGG keyboards, the iPad mini doesn't fit in a slot for typing. There is a stand that pops out of the back of the case for propping the tablet up for typing.

The iPad mini pops easily in and out of the Mini 9 and totally protects the tablet when in the case. This keyboard turns the little iPad mini into a decent production machine for writing.

Dimensions: 8.13x5.75x0.88 inches; 10.5 ounces (without iPad mini)

Don't miss the full review by James Kendrick on ZDNet .

$49.99 from ZAGG