Depends on what build you are. If you are a cold sorc i would use cold facet. If you are a fire or light sorc you shouldn't waste the RBF. Cause fire and light already have a +dmg mastery. The + damage of RBF won't help a lot. You would get +1% dmg or so instead of 5%.
I've been trying to trade this thing for a shako and hoz for my hammerdin, but people seem to think its not worth much. On the trading page for U.S. East ladder it says it is worth an Ist and a Mal rune which is more than a shako and hoz. I am a blizzard sorc, but I like my pld more than my sorc which is why I'm trying to trade it. One person offered me a Ko rune for it which is complete bs.
Whenever you want to trade something for it's actual value, use the trading forums on this site or the like. No one in Diablo II has a clue what stuff is worth, and the few that do will try to rip you off anyways.