Depends on the use and guage for me.
Pros: 1) I enjoyed wearing a barbell in large guages, specifically because I don't want to guage down below a 2ga, but I do enjoy the large guage feel. A large guage CBR will inevevitably guage you down. 2) NOTHING beats the feel of a barbell while I j/o unassisted. Feeling it slide back and forth in me while I stroke is very much unlike a CBR that just rolls around. 3) You don't need plyers to remove the ball off like many large guage CBR require, and the ones that don't are more expensive.
Cons: 1) It makes it harder for me to control the urine stream with a barbell since it tends to spray in opposing directions. A 2 ga CBR is much easier to use at the urinal than a 2ga barbell, otherwise use the stall. 2) Good luck finding a long enough heavy gauge barbell, they are tough to find. You'll prob have to special order them or get them online. 3) The barbell has a nasty habit (on me) of sliding back into my dick if the ball on the front end is too small, which they tend to be on a barbell, so I have to put a much larger ball on the end instead.
I'd say for looks, or if you're planning on getting kinky with it, stick to a CBR, because they are more fun. A barbell to me feels better and is more practical for every day use once you learn the ins and outs.
For 10 and 8ga rings, I'd stick to a CBR, the barbells with go right through me and do not stay in well. For a different look, try rubber tipped balls that come in different shapes, like the spiked ones or even black-light glowing ones. For extreem kinky guys, try a padlock, or even link up your older/smaller CBRs together in increasing size to the one you're wearing now. Prince's wands are (I hear) the ultimate in jewelry attire and not for the faint of heart, and have to be customized. $$$.