If You are in Australia Digi-Key (Australia) is offering Vero 29 COBs At A$34.99. This compares favourably with Mr Jerry even if you could get him down to US$25 a cob. Spend over A$200 and its free postage (from the US!! Amazing!) until Feb 18.
This is why I went with the Vero's, and mounted them without screws. I plan to just reuse my heat sinks for better lights as they come on the market at reasonable prices. Figure Vero improves 10-15% year over year, and as efficiency increases there is a corresponding decrease in heat output, in theory one should be able to get a lot more light output on the same heat sink in two years.
Jf you are here in Australia the cost of a cxb3070 ranges from AU$47 - 88. Even from Kingbrite they are asking US$40 which translates as AU$58. Dont even ask about the cxb3590.