Ed,
They are easy to turn, the minicones ones are consistent but getting a really smooth finish across the point at which the mini cones can be an issue, patience required, the burr ones are easy, you need to go easy at the outset as the material density varies, so its small cuts , then get used to it.
I thoroughly enjoyed turning them, but they should be reserved for that special pen! Too costly otherwise, although the Atrax that I pictured above spent ten minutes on the stall at £50.