iwerkz Folding Bluetooth Keyboard ($30)
4 out of 5 stars
The iwerkz Foldable Bluetooth Keyboard is ultra-portable and works nicely with iPhones and iPads. When folded, it slides into an included hard case. The case also functions as a stand to position your iPhone or iPad while you're typing. When folded the keyboard is less than one-inch thick.
Set up was easy. To pair the keyboard with my phone, I had to enter a connection code and it paired right away.
I liked the feel of the keys on the keyboard, but because of the fold, the keyboard is stretched out. For example, it takes some argument with my muscle memory to stretch my left index finger all the way out to hit the "B" key. It's not where it would be on a regular keyboard. It definitely slowed down my typing, but I still typed faster with the keyboard than I would if I was just using my thumbs on my phone or iPad's keyboard. And, I believe with more practice I would get used to the key positioning. 
The iwerkz keyboard comes with a USB charging cable and a protective case/stand. It comes in five different colors: red, blue, pink, black, or white.
Pros: The keyboard is extremely-slim and has an ultra-portable design. The hard case also can be used as a stand for your iPhone/iPad while typing.
Cons: The fold stretches out the keyboard and takes a little extra effort to hit the right keys.
The Final Verdict: Because of the easy portability, I will be taking the iwerkz keyboard with me on all my trips despite the keys stretched out at the fold. I may even keep it in my purse at all times in case the spirit moves me to start writing a best-selling novel on my iPhone. Or, at the very least, a decent sized email.