Well, we've just been fingers-on with both the 23-inch Acer Aspire 5600U and the 27-inch 7600U in London, and we can report that the touch interface was totally fluid.
Specifically, the Wall Street Journal reported yesterday that Microsoft reps in Taipei found it difficult to navigate their own OS due to hardware issues with their demo devices -- namely, new all-in-one PCs from Acer and ASUS. There were said to be issues with opening and closing apps, possibly due to the implementation of touch on such large screen sizes of 23-inches and over.