I have been using the Apple Wireless Bluetooth Keyboard for a while now. While I like it, I wanted to try the Logitech alternative. I'm happy to report that the experience has been completely positive for me, and that the Logitech has replaced my Apple keyboard in my travel bag.
The first benefit is that the keys feel more "solid" on the Logitech. It could be because the whole keyboard is a tiny bit thicker, or it might be the material they use for the keys, but to me the Logitech has better play with the keys than the Apple version. I type better with it. The keys are slightly smaller than the Apple keyboard, but they also have a little more space between them, making my style of typing a lot more accurate with my large fingers.
The Logitech keyboard has one less row of keys, thanks to the inclusion of the Function key. That means it's not as "tall" as the Apple, but it is, unfortunately, a little wider than then Apple. This means that with my Targus netbook bag it's a tight fit. It does fit, but it's definitely pressing the sides out a bit.
What really sells me on this keyboard is the power switch to clearly and obviously turn it off, thus keeping batteries well-charged and not triggering functions on the iPad when the keyboard gets bumped. With the Apple keyboard, it shuts off automatically but wakes up when keys are tapped. This meant I had to turn off Bluetooth in my iPad when not using the keyboard; An extra step I can choose to skip now, with the Logitech.
Another big selling point is the case/stand that comes with this keyboard. While my Smart Cover works fine for landscape, it doesn't allow portrait orientation with any sort of slant. The Logitech keyboard cover converts into a sturdy stand that lets me switch to a landscape orientation. This is very handy for editing documents!
Of course, the Bluetooth connection is easy to establish, and the keyboard never misses a stroke. I"m very pleased with the way it functions.
If you're in the market for a Bluetooth keyboard to use with your iPad, and are trying to decide between Apple and Logitech, I would say it comes down to your personal preference. They both have great features and offer quality. However, I think the Logitech has the advantage in feel, extra features, and user-friendliness.
For the price, you can't go wrong.