I loved all the events at Epcot. All the storytellers are so engaging and different and interesting. You can sample all the different snacks and drinks, they have a few new booths with special holiday selections this year. Depending on the narrator, you might even be able to grab a back row seat for Candle light processional.
I admit, I have not seen Jingle Bam in person, but I would choose World Showcase over it. It just doesn't look that great to me, it looks really crowded and I hate having to spend so much time saving a spot.