An external keyboard is likely to be an iPad must-have for quick text entry. For years I've wished for an external keyboard link to the iPhone, so I'm keen to get my hands on the new keyboard dock for the iPad. While the new dock/keyboard has a number of unique attributes, including the ability to charge your device and a slew of dedicated keys, it is nearly twice as heavy as the standard Apple Bluetooth keyboard and, because of the fixed dock attachment, nowhere near as easy to carry around.
I will certainly try both options. I suspect I will use the new keyboard and dock mainly at home. For everyday travels I feel the lighter Bluetooth keyboard will be the choice. Apart from other aspects, you are not stuck with the portrait display as you are with the dedicated unit. When my new Piel Frama leather case arrives (ahead of the iPad, sadly) I will be able to set up the iPad at a good viewing angle and have the ability to move the keyboard around to a comfortable position. And, of course, in landscape mode you can easily plug in a charging cable while working.
While the jury is out, MacWorld have done the first full review of the dock/keyboard and, at $69 it is a recommended accessory.