I'm not a video-processing expert, but this seems to be the breakdown for chips found in consumer grade equipment.
1.
Silicon Optix Realta: S-Marts top of the line! Realta will scale to 2560x1600p, can handle less common cadences such as 6:4 and 8:7, and supports noise reduction on HD signals
2.
Silicon Optix ReonVX: There is essentially no difference in deinterlace and scaling performance between the ReonVX and Realta. But the: ReonVX is limited to 1920x1080p and only supports noise and block reduction on SD.
3.
Faroudja DCDi: a very solid performer, but has been known to cause macro blocking issues when mated to some displays. This problem may not be an issue with the newer chipsets from Genesis, but I haven’t found any information to suggest otherwise.
However, it all comes down to how well the manufacture implements the chipset in their product. Which adds another set of variables to consider besides just the processor that is used in a particular product.
IMO