I have never owned one and have no plans on purchasing one. I just really dislike the look. To my eye it is so out of proportion that I could never see myself smoking one. I have also noticed that many have thin walled bowls which would force me to change my smoking cadence. I did that one time with a Rad Davis Belge that had thin walls and i never did it again. Rad or no Rad. I don't change my cadence for no one. All my pipes smoke in the range that I prefer.
I also go the other way with walls that are 10 feet thick and the pipe weighs a kilo. I have found my favorites are all group 4-5 sized pipes in the 40-55 gram weight range.