Can't say i've had that model. I just got rid of an Acer X193HQ a couple of days ago. They are a good range i'd say. I got a BenQ G2220HD as an upgrade, which is the same size as the one you mentioned. Are you thinking of buying this or ?
I noticed it on Bit-Tech "Acer S1 series: Ultra thin LED Displays, the slimmest in the world!" http://www.bit-tech.net/news/industry/2010/07/16/acer-s1-series-ultra-thin-led-displays-the/1 It says it's less than 15mm thick but i can't find any decent reviews online for it so wondered if anybody owned one to comment.