I havent looked at the asus montiors that are 120hz. One of the main reasons I have it narrowed down to the acer and alienware is because of their base stands. Those circular ones just look horrible to me.
Both the acer and alienware perform well. I have read reviews on newegg of people receiving monitors with dead pixels or half the screen dying out, while others have been extremely happy with it. Not sure if it is a glitch or if they are running 120hz at some wierd resolution that makes it happen.
The only review I can seem to find on the asus is a review showing how good it is, but it does not compare it to the acer or the alienware, so it is a relatively pointless review. Any of these 120hz monitors will outperform a 60hz monitor easily. I am personally leaning towards the alienware. It seems more user friendly and it operates better than the acer, but I do agree, that is a big price tag, especially for someone like me who wants a surround setup.
Here is the review comparing the acer and alienware:
Hope this info helps you out a little bit.