text: three piece is far superior to a one piece slate , a one piece is really only reserved for cheap or bar style tables , a three piece slate you can level each piece indivually to the frame with wedges under the slate liner and it can be perfect , a one piece will never be perfect , you cant effictivly level  the slate , if it has a crown or dip in one end what ever you do to fix that spot will ultimately effect the other areas of the piece somewhere ......Thre piece is the way , Olhausen make a top notch table, and the slate they use is the best , they use genuine Italian slate , manafuactured by OIS ..good stuff ......