The truth is Carbon and Ceramic infrared sauna heaters are both beneficial in different ways.
Carbon Infrared Heaters have a lower surface temperature, so they produce longer infrared rays which penetrate deeper into the body. However, they do not produce a lot of infrared heat.
The first thing i noticed when using an infrared sauna with carbon infrared sauna heaters, was that it did not heat the body that fast, so it took a long time to start sweating.
Ceramic Infrared Heaters have a slightly higher surface temperature so they produce slightly shorter infrared waves, but are still very beneficial. They also produce a lot of infrared heat, which heats the sauna cabin faster and more efficiently.
When I used this type of sauna I definitely began to sweat faster and the heat wasn't to much to handle. You can sit in one for 45 min to and hour easily.
There is one company called Clearlight Infrared Sauna that'makes a carbon/ceramic infraredd sauna heater. I have not been able to find a infrared heater like it. Probably because it is their exclusive technology. There website is www.infraredsauna.com.
The site had a good article on carbon and ceramic heaters