I havent seen a VGA Box available in India anywhere. Anyways I dont understand what you mean by "XCM or YPbPr to RGBHV". XCM is a brand while YPbPr to RGBHV is the process the component cables give YPbPr which is converted to the VGA standard RGB HV. XCM or any other similar transcoder does the same thing.
As for the quality I am not sure which is the best, but I have been recommended the XCM one by multiple people. Also the XCM on PlayAsia.com is the cheapest I have found any place unless you have someone in US who can get it along with them. There are other ways for getting VGA out of PS3 on a non HDCP compliant monitor, but all of them are costlier than this VGA box. In Fact theres a HDMI to VGA convertor, but its selling for $150 in the US.
Anyways I have ordered the XCM VGA Box from PlayAsia yesterday. Its already shipped out (Free bubblewrap shipping), Not sure how much time it takes to reach.