Jim,
I have one as well and it really does what it is intended to. It does add some weight to you cue but the alternative, stretching and missing, is much worse. I have used it on some really high end cues and have no troubles with it messing up the finish. I think it is very safe and I am very happy with mine. The one problem that I have is that I have no where to put it in my Justis case.. I usually leave mine at home when going to the pool room but it is very nice.
A good investment, IMHO.
Peace,
Joe Koontz