I have owned and listened to both and currently use (and prefer) the King Cobra in MY system.
Grant and the folks at Shunyata seem very excited about the Python and from what I've read, recommend it above even the King Cobra.
When used on the source component all high end Shunyata's are very refined and remove the digital hash quite well. Above most any other high end power cord, Shunyata's seem to transform digital into an analog type presentation. Each of the Shunyata's has it's own character, and therefore unlike the folks at the company who seem to market their products with hype, I cannot say which is "BETTER" since the character each cord imposes on a system is different. Not better, not worse... just different.
Starting with the Viper V2 - Use this cable if you feel your system needs more textured midrange. Sweetness in the highs and a very surreal sound quality that makes listening fun. Mids are velvety and rich.
Python - I found this cord to be very dynamic and has a pronounced midrange. Works great if your system needs a more forward midrange. Highs are similar to the Viper but dynamic swings are far superior.
King Cobra - very polite. very analog. very hard to tell that anything changed. The King Cobra can be praised for what it doesn't do more so than what it does. It seems to neither take or give....it just makes things right. There is no spotlighted midrange, no surreal texture, no ultra dynamics. Just music.
Hope this helps.