I use a sharp skew to cut the beads and have been pretty lucky so far...no tear-out problems.
On the o-ring question, pen sales are a complete mystery to me...eventually everything sells, but there doesn’t seem to be any hard-and-fast rules for what sells first or best. About 1 in 20 of my pens have o-rings, and the feedback I get indicates that a lot of people like the non-slip feel. There is one downside to these o-rings however...I've noticed that in one shop in particular, where its usually very hot and the humidity is extremely low, the black o-rings will crack after a few months of shelf-time.