I use steb centres all the time, quick and easy and during production turning there is no need to turn the machine on and off all the time. The steb centre also comes into its own when doing tuition as a catch with a steb centre in place is never as catastrophic as one when using a pronged drive. Students are less likely to be panicked as all that happens is the wood stops going round. I also find it easier to remount and centre again that using a pronged drive.
I have just had a look at the ones shown above, one of the beauties of steb centre drives is you can reverse run the lathe using it, with a 4 prong unit there is a chance it will come out, looking at the ones shown it appears that the drive teeth are directional, for me that would be enough to put me off buying this set.
