The music is piped in to both restaurants, but at California Grill you can go out to the platform and watch Wishes outside if your table is far away from the windows.
I've had a window table at both restaurants during Wishes, and my choice for watching it from a table would be at Narcoossee's (watching fireworks from ground level is better than watching them from above, IMO). Especially if I could get the great table we had last time!
But for a guaranteed good view, I'd go for California Grill. That way, no matter where you end up in the restaurant, you can get up and join the other diners outside for a worthwhile view of the fireworks.