I've turned several (maybe 15-20 or so?) bowls from hickory; shagbark and pignut. Both turned very well, but as Mark mentioned, it seems to be prone to checking. I found after losing a couple to large cracks, that tiny little checks that you missed turn into large, open cracks when drying. I found that turning them quite thin worked well for me---less than 3/8". I still got a few cracks around the tenons which I left on during drying to make sanding easier. The wood I turned was much too wet to sand right away. I made a couple very nice sets of spalted hickory that had amazing color--they are in my gallery. The rest of the tree was just whitish bland hickory colored. This spalting had no soft spots, amazingly! Right now I have a few pecan bowls drying. Now you think hickory is hard, try pecan (a type of hickory, really)....
One last thing I should mention is that it moved a lot during drying. So much that when I thought it was dry and removed the tenons, a couple wobbled a bit after the moisture content in the finished bowl equalized....DOH. I've had the same problem with American Beech. The concave bottoms seemed to reverse themselves........