I was also searching for alternatives for the DR800S(G).
The Asus looks pretty nice and seems to be an interesting alternative to the DR800SG. But it's not an alternative because it's not available yet.
You don't want to wait any longer for the DR800? Then you also have to find another alternative then the Asus DR950.
I was already thinking of buying an Amazon Kindle DX but the PDF features + missing ePub Support killed the device.
Right now NO device on the market is fitting my wishes. The DR800S(G) will, as soon as it gets the pdf zoom and annotation feature implemented.