I hit google and this was at the top of the list
Copy paste from the report:
PLASTIC AND WOODEN CUTTING BOARDS
Dean O. Cliver, Ph.D
We began our research comparing plastic and wooden cutting boards after the U.S. Department of Agriculture told us they had no scientific evidence to support their recommendation that plastic, rather than wooden cutting boards be used in home kitchens. Then and since, the U.S. Department of Agriculture's Meat and Poultry Inspection Manual (official regulations) and the U.S. Food and Drug Administration's 1999 Food Code (recommended regulations for restaurants and retail food sales in the various states of the U.S.) permit use of cutting boards made of maple or similar close-grained hardwood. They do not specifically authorize acceptable plastic materials, nor do they specify how plastic surfaces must be maintained.
Ther was more but I was afraid not all of it could be posted in this forum. What I think is the other facet of a cutting board is that it take the abuse of the blade and not dull the edge faster. Maybe someone can find a test that has a comparison of knife edge sharpness after so many ... 100 strokes? at x amount of pressure across a given surface. If the risk of bacteria is no better or no worse the surface that dulls the expensive knives the least would be the winner IMHO