My flat mate has one of those new Fusion based Netbooks. Seems pretty good. Could see the next gen of them in an Air. Considering getting one myself when I find one not made by Acer.
AMD E-350's CPU is noticeably worse than the C2Ds in MBAs. It is better than Atom but can't fight against Intel's premium CPUs, especially if we take Sandy Bridge into consideration. The IGP is wonderful though.
Llano will hopefully change this since Zacate is meant for netbook and other cheap laptops. Llano will hopefully bring low-voltage chips meant for ultraportables like MBA. So far there are no news though.
http://www.anandtech.com/show/4023/the-brazos-performance-preview-amd-e350-benchmarked