I do and I love it, stays much cooler during the hot summer and is also warm during the winter.
This is mine where I keep the show horses, has 8 stalls w/runs, cement clipping/washstall area and also cement feed room, I don't remember its exact measurments but I think it is 35 wide, 65 long.
I once worked on a farm with a block barn..and Erica is right! They are warmer than other barns in the winter, and cool in the summer. I wouldn't hesitate to have one!