The computer I had before the M7 was HP TX-2. It too had a touchscreen but had a matte finish to it. It died due to other design flaws (poor airflow caused overheating) but the touchscreen was the thing that drew me to it.
In the case of the M7 its other features outweigh the glossy touchscreen. I just don't use the touch features on it. Besides, as I said, it isn't a true tablet but a big laptop. So a touchscreen with multigesture capabilities seems pretty useless on it.