I have five markers and use freaks on all of them....... I've got all of the fronts and a back for each marker........ all in all about four full freak sets, usualy picked up when I bought the markers.
So I am being pretty impartial when I say........... I'm sick of them, gimme a pipe
My main worry is that this super accurate 0.01mm insert relies on a couple of o-rings to centre it whereas the pipe etc.... are a nice solid screw-together.