I got the Apple Wireless soon after I got my iPad first gen, and have never looked back. I stopped carrying around my Macbook soon thereafter.
If you're a writer, and especially a touch typist, there's no comparing the speed and accuracy you can get from a physical keyboard - hearing key clicks is one thing, tactile feedback is another.
There are some issues carrying around a keyboard that lacks an on/off switch (why, Jonny, why?) - if you leave Bluetooth on and jam the keyboard into a day pack... well, each errant key press is going to wake the iPad and drain a bit more of the battery (wake-on-key press is a feature, not a bug). So, before I stuff the iPad and keyboard back in my pack, I have to go to Settings to turn off Bluetooth (well, you could remove the battery from the keyboard, but that's even more of a bother). While I love the feel of the Apple Wireless and long ago learned to live with its one shortcoming, if you can find a keyboard that feels good to you that also has a mechanical on/off switch (or equivalent)....