Yes, I do sort of. Think mine were picked up at one of Chester Machine tools Open Days (Open Days, remember them?) but I think they are all a generic Ying Tong offering. I use them very seldom but when needed they are a lifesaver. I have seen them all on the various stands at the shows and they are all pretty much identical.
Probably all roll off the same production line, they last if you only give them a gentle tap. I only use them for marking and then swap over to a proper punch.
I got some from Arc Euro trade, and as Bob says they probable come off the same production line. The ones I have are undersize so they fit in the hole, but there isnt much consistency with the amount they are undersize, but I guess it depends how accurate you're needing to be.
the "cheapo" sets are all ok for what they are supposed to do.... transfer marks, not centre punch, a light tap is all they need, just enough to leave a clear mark
I use transfer screws. Also known as cone point grub screws - usable as is but could do with cutting a sharper point on lathe. The odd occasion where I have an unthreaded hole to mark they are good enough for what Im doing, I am usually marking from threaded holes.