Imagine if your computers keyboard was replaced by a sheet of glass, how enjoyable would it be to type? Personally I enjoy the 'tactile' feel of a 'standard' keyboard. I've used the touchstream keyboards in the past, they had no 'tactile' feedback and just didn't feel right. The iPhone got rid of that 'tactiliness' for a more radical, and in my opinion fad-like, approach. Not everyone will enjoy 'typing' onto a flat surface.