Going head-to-head with Apple is a dicey situation, but apparently AZiO thinks they've found a niche for their Bluetooth keyboard. Now that you can use BT keyboards with all iOS 4.x devices, you should consider adding one. AZiO says on their website that the virtual keyboard may be fine for travel, but when you're using your iOS device at work or home you may want a full keyboard. However, I could really use a portable keyboard when I travel. Perhaps it's because when I'm at home, I do most of my typing on a MacBook Pro with a full-size wired USB keyboard. But on the road, lately with just an iPad, an external keyboard would be great for typing articles and long emails.
While the AZiO keyboard looks a heck of a lot like the Apple one, there are some differences, both pro and con. Apple uses aluminum whereas AZiO uses plastic and paint. They both have the same chicklet style keyboard but AZiO manages to squeeze in a few more keys, including F1 to F16 function keys plus Home, End, PageUp and PageDown although iOS may not know what to do with all of those buttons, for now. Apple recently revised their wireless keyboard to use two AA batteries instead of three, but the AZiO uses two AAA batteries.
At $69 for the Apple keyboard, I'd hesitate to leaving one in my travel bag, but for under $50, the AZiO KB333BM makes a nice portable keyboard that can do double duty with your Mac and iOS devices.