As expected, the C3 processor is not able to compete with other processors at similar clock speeds. Depending on the particular benchmark, an old Celeron 667 is either considerably faster or considerably slower, making it difficult to specify a recommendation for VIA's C3.
The C3 has definitely won the power and temperature race: no other desktop processor consumes as little energy and wastes as little power as the C3. Looking at performance and power output in terms of a ratio, the C3 blows away its competitors. Congratulations to VIA for designing a processor that provides the most performance per Watt, finally showing that sufficient processing performance does not necessarily entail high power consumption.
Thus, the C3 can basically be cooled passively, without a fan. While desktop systems won't benefit much from this, set-top boxes and other hardware that require some sort of computer capability are given timely performance at little design efforts.
Think about huge server racks consisting of dozens of C3 systems, cooled only by a handful of fans. Administrators do not have to fear performance drops or dead processors with the death of a single processor fan. VIA's C3 will continue its work unimpressively, as it does not require much power anyway.
The most interesting fact about VIA's Gigahertz-C3 is its attractive price, which should quickly fall to approximately $70. It's certainly not much to ask for a processor that won't rock the boat, but it certainly has more trend-setting aspects than the enduring performance battle between AMD and Intel.
I think hardly anybody would expect supreme performance from a low-power processor. However, what about a successor that performs almost as good as a Pentium 4, but remains at this low a power level? That processor might just be called the C4!