We ate at both restaurants in June, so I can compare. Our whole family loved both restaurants.
Coral Reef was a lunch for us. Wonderful rolls and butter. The lobster bisque was excellent and I had to keep my daughter from eating all of mine. The adult entrees were also very good - no complaints whatsover. One child got the grilled Mahi child's meal and I have to say that it was the best tasting child's meal I have ever, ever seen, but it was not chicken nuggets/mac&cheese. The kid's pizza was fine too. The only disappointment was the kid's pasta with white sauce. Absolutely nasty and I told my son not to eat it and he shared my daughter's pizza which was too much for her anyway. We were too full for dessert and we are not terribly light eaters, so I didn't leave thinking the portions were skimpy. The highlight for the kids, of course, was watching the aquarium which all of the tiered booths face. We have eaten here on each trip and not been disappointed.
Teppanyaki was another excellent meal. This time, BD dinner for my husband. We knew the kids would like it, as we do this often at home. Chef was nothing special, but food was wonderful and they brought out a delicious BD cake. I will say that I was nervous the whole time about my 4yo and the hot cooking surface. I guess in the interest of fitting in as many tables as possible, these table do not seem to allow as much distance from the hot surface as what I have seen in some of the other chains. My son could definitely reach the cooking surface, so we had to be vigilant. My kids all get the shrimp kids meal at all the teppan restaurants and they had fun with the rigged chopsticks.
Either restaurant would be an excellent choice, but Coral Reef is definitely more unusual. You can Benihana anywhere and this is no different, but there are, as far as I know, no other restaurants where you can watch a full wall aquarium while you eat.
Ok, just asked the kids and two voted for Teppanyaki, and one for Coral Reef. She also reminded me that they made a big fire on the cooking surface during the meal that might scare little kids.