The fact that the Samsung NC20 netbook is not based on the Intel Atom CPU was already leaked a month ago from a Russian site that reviewed the NC20. Today VIA announced officially that the new Samsung NC20 netbook is based on the Atom competitor VIA Nano CPU.
The NC20 pushes the size limits of netbooks to a 12.1 inch screen with 1280x800px resolution.
Other features of the NC20 include 1.3+GHz VIA Nano processor with the highly-integrated VIA VX800 system media processor, 1GB RAM, 160GB HDD, 802.11b/g, Bluetooth, 6.5h battery life, card reader, 3 USB ports and 1.3MP camera.
Measurements of the Samsung NC20 are 292.4mm x 217mm x 30.7mm and the weight is 1.52kg.

The VIA Nano processor family leverages 65 nanometer process technology for enhanced power efficiency, and augments that with power and thermal management features within the compact 21mm x 21mm nanoBGA2 package for an idle power as low as 100mW (0.1W).

If a VIA Nano based netbook is better or worse than a Intel Atom based one is not easy to answer yet. Intel Atom has dominated the netbook market and VIA is just getting some traction. Pricing will be a big factor in this CPU battle on the low end.
Shop for Samsung NC netbooks on Amazon.com.