Nvidia has recently made a major push to show the viability of Tegra in netbooks. Tegra based prototypes have been showing up at industry trade shows since the beginning of the year. Some of the notable devices included netbooks by HP and ASUS which were essentially the same as the products already available on stores shelves but with Tegra chips running inside them instead of Intel's Atom.
Coming up with any kind of definitive performance comparison is hard at this point. Demos, afterall, are meant to show the item being demoed in a good light. One difference that is instantly notable, however, is that Tegra netbooks run Windows CE, not Windows XP. Windows CE is a version of Windows designed by Microsoft specifically for MIDs. Unfortunately, it is not being used because it actually better than Windows XP in any way. Its use is simply due to Tegra being an ARM processor, and thus not x86 compatible. Windows CE is a very basic operating system, lacking in feature such as Windows Update and Windows Security Center. Windows CE is also not compatible with many popular programs. For example, the latest version of Internet Explorer available for Windows CE is IE6, although Nvidia showed a port of Firefox 3.5 which could become available along side Tegra netbooks.
That catch aside - and it is a big one - Tegra based netbooks seem to work modestly well. The real question is the one that absolutely cannot be tested in a demo environment, and that is battery life. Tegra certainly looks as if it could provide outstanding battery life, given its modest performance, its original design intention as a processor for MIDs, and its system-on-a-chip design. That said, the best Atom based netbooks are coming close to providing 10 hours, so Tegra will have its work cut out for it.