Are you guys sniffing burnt capacitors or something? SiS and VIA both make fast, stable and feature-filled chipsets for socket 478. Sure, the Intel chipsets may be more popular and the 875P may hold the "1% faster" performance crown, but SiS and VIA do make competitive chipsets. The only feature I can think of that the Intel chipsets have over the alternatives is the CSA network port. Most Intel chipset boards on the market have cheaper network alternatives, so unless you explicitly were looking for the CSA NIC, no difference there. The only big issue right now is that these boards using alternate chipsets seem difficult to find, but then again socket 478 choices seem dwindling overall.
VIA's chipset is the PT880.
I reviewed my MSI PT880 Neo-LSR here. Generally speaking, most of the VIA boards are limited to about 220MHz FSB. They do have a working AGP/PCI lock. The boards are cheaper than Intel chipset boards. My MSI board has full overclocking features (except only up to 1.60vcore).
SiS has the 655FX and 655TX chipsets. Don't know what the difference was, but those chipsets also support dual channel RAM, AGP/PCI lock, yadda yadda. Asus made some great boards using these chipsets that were excellend overclockers. They seem to be really similar to the Intel chipsets even up to very high FSB speeds (250MHz+).