Although it's a smash hit, Apple's iPad isn't winning the hearts of users who find it difficult to type on its onscreen keyboard. And even for many who love their iPads for other things and can type shorter items on the screen, the lack of a physical keyboard has meant they still must turn to their laptops for intensive typing tasks.

One solution to this dilemma has been to carry a separate wireless keyboard. But that means carrying two things. So a number of companies offer protective cases for the iPad 2 with low-profile, but real, keyboards built right into their inner surfaces. These keyboards appear when you open the cases, which act as stands for the tablet while you type.

I've been testing four such iPad 2 combo keyboard cases, each of which lists for $100. I also took a look at a slightlydifferent accessory" target="_blank" title="n.附件；帮凶 a.附属的">accessory, a new full-size $130 keyboard and stand for the iPad 2 that folds up and holds the tablet for carrying, though it doesn't cover or protect the screen.

If I were personally going to buy one of these, it would likely be the Logitech Keyboard Case for iPad 2, a thin, light and sturdyaluminumenclosure with a keyboard I liked. But this is a personal decision, involving the look and shape of the case, the feel of the keyboard and the angles at which they prop up the iPad. I stronglyrecommend going to a store and trying some before choosing one.

Though these rival cases differ, they all have certain things in common. They all make the beautiful, slim iPad 2 much bulkier and heavier. Also, the keyboards inside these cases require recharging after a few weeks or months, depending on how heavily they're used. And none comes with a charger" target="_blank" title="n.军马；委托者；控诉者">charger. You have to charge them from a laptop, or by using the wall adapter that you use to charge the iPad itself, or another USB-compatible charger" target="_blank" title="n.军马；委托者；控诉者">charger.

In addition, these cases only work well for typing when you place them on a flat surface. And I found they make it clumsier to hold the iPad for reading. They have special keys for such things as replicating the iPad's home button; searching; volume; copy, cut and paste; and controlling music and video playback. Most also switch the iPad's screen on and off when you open or close them. Finally, with each keyboard, you have to perform a simple, one-time Bluetooth 'pairing' process with the iPad the first time you use them.

Here are some features and downsides to the cases and keyboards I tested.

This is the simplest of the keyboard cases I tested. It's just a thin, rigid aluminum tray with a recessed keyboard in the bottom. To use it as a carrying case, you snap your iPad 2 into the tray, where it's held tight by rubbery pads in the corners that keep the screen from touching the keyboard. You can still charge the iPad while it's in the case. When you're ready to type, you remove the iPad 2 and stand it up in a groove above the top row of keys, in either a horizontal or vertical position.

This case is the only one I tried that doesn't completely cover the iPad 2. I found it to be lighter, thinner and yet sturdier than the others. I also liked the feel of its keyboard and found the angle at which it held the iPad to be excellent. The product was developed by a small company called Zagg, which made a similar case for the original iPad. Logitech is coming out later this month with a version for the 10.1-inch Samsung Galaxy Tabtablet.

Zagg also has come out with its own new design for the iPad 2, a hard-plastic wraparound case that completely covers the tablet. The iPad snaps inside the top cover, and the cover, when opened, tilts forward to allow the tablet to nestle into a groove in a keyboard that is almost identical to that of the Logitech. One difference: The folio allows the iPad 2 to be used only in horizontal mode while in the case.

The first units of the folio, which came out in July, had a defective closure. That has been fixed and the company is offering to replace the early units. I tested the revised version and it closes tightly. This case, the only one of those I tested that had a removable keyboard, also had the best-aligned cutouts for the iPad 2's buttons and ports of the wraparound models tested.

This is a soft-plastic case that, like the Zagg, stores the iPad 2 inside the top lid and places the keyboard inside the bottom lid. It has no latch, and doesn't switch the iPad screen on and off. The Kensington differs from the others in that it has a swivel mechanism that allows the iPad 2 to be used vertically or horizontally while tucked into the top cover. However, I found the angle at which it placed the screen to be too straight for comfortable viewing while typing. And, in vertical mode, I found the screen was a bit wobbly. I liked the feel of the keyboard, but it was the only wraparound that lacked dedicated buttons for copy, cut and paste.

This is another soft plastic wraparound model, but I found it too complicated and bulky. It tucks the keyboard under the top flap that holds the iPad 2, so you can use it as just a stand. But this made it thick and, to my eye, odd-looking, when closed. On the plus side, it offers multiple angles, though it only allows horizontal use of the iPad.

I found the keyboard more cramped than those on the others. I also found the iPad hardest to insert and remove on the Belkin, and the holes for the ports and buttons to be the least aligned.

This isn't actually a case and it doesn't protect the screen at all. Instead, its main selling point is that, unlike the others, it packs in a full-size keyboard that protrudes beyond the iPad's dimensions via a clever design. The keyboard is hinged in the middle and folds out from beneath a hard-plastic cradle that holds the iPad 2 face up and allows access to all the ports and buttons. When the keyboard unfolds, it raises the iPad into a standing position, in horizontal orientation. It probably will appeal most to people just carrying an iPad around the office or home. It costs $130, and, to protect the screen, you'd have to shell out another $40 for Apple's own screen cover. It will be unveiled next week and available in September.

Watch a video of Walt Mossberg on iPad 2 keyboard cases at WSJ.com/PersonalTech.