I ate at both on our last trip. I was glad to eat at Coral Reef, I had always wanted to eat there and it was nice, but nothing really great. To be honest, I don't even remember what I ate, so it wasn't memorable food wise. But I was glad to go for the experience, if not for the food.
Teppan Edo was excellent food. I agree with the PP about the group that you're seated with, if you have people that are sort of "blah" it won't be as fun. I will say that you should definitely have an earlier ressie. We had a late one b/c it was just my partner and I and we were doing F&W...well we had to wait for 90 minutes before we checked back and were told they were going to bump our reservation. Needless to say, myself and several others were quite upset and they ended up seating us. Great meal, lots of fun.