I have seen cool blocks recommended here many time.
A book I got from the library said that steel blocks are badly unrated. Heat is not a problem; the only reason not to use them is that they will not support a really small blade properly without risking damage to the teeth. Then he recommends maple blocks; they wear out faster than cool blocks, but are free.
Also, I have seen a composite block on ebay that claims it is better than cool blocks. Anyone tried it?
Comments?