Cometic Aramid Fiber Head Gaskets

[Windsor377]

One of my partners recently pointed out the Cometic aramid fiber head gaskets. When I go to there web site, it seems to be shown as a lesser gasket compared to the dead soft copper.

Is that my mis-read? Does anyone know if it has good, bad, or better thermal transfer properties compared to copper? How about re-useability?...AND, are they compatible with existing O-rings and receiver grooves?

Thanks in advance.