Yes they do. How much depends - as usual - on a combination of material, skill and tool quality.
Some people report that they get an externally raised area, but I can't say I've ever been troubled by that.
I do get an internally raised lip though, so the slick thing is to mount the starnut first, before the cut.
I like using it, but it's not like I'm not stumped w/out the pipe cutter. Cuts get straight and burr free.