I have just started using the ZaggMate and I am really happy to have purchased this device.
If you need to enter more than a few lines of text, the virtual keyboard just isn't suitable.
The nice thing about the ZaggMate is that you can use the iPad as a notebook computer (i.e. on your lap) and it doesn't get hot.
A bonus, you get the cursor keys that are missing from the virtual keyboard.