I've been to all three. Le Cellier twice, Coral Reef twice, and San Angel once. I did not enjoy San Angel. I don't plan on trying it again. The decor was nice, but I'm spoiled by the Blue Bayou at DL, so I wasn't that impressed by it. Also, we didn't have a prime table so that probably didn't help. It was the worst meal of our trip, and unfortunately, it was on our last night! But, that was in 2006. There are a few out there that really love this place, so if you really want to try it, go ahead and do so, but be warned that this place earns mediocre reviews, at best.
Coral Reef is hit and miss with my family. It's either really yummy or just really bad. I think they easily get behind on ADR times in the evening. The first time I went the service crawled. We were there for over two hours... after waiting 45 minutes past our ADR time. We had checked in early, even. We were on the DDP and we had to take our desserts to go to run and catch Illuminations. Problem was that they would only package up one of their desserts because they others contained alcohol, and DH was not a happy camper about this. He hates being rushed out of a restaurant. The second time we went DH liked his meal less, but I loved mine (whereas the first trip I thought my entree was pretty gross, but DH LOVED his - favorite meal of the trip). We made ressies for the first lunch seating, so no waiting, got a table right by the tank, and service was much faster. With this one I'd say go to enjoy the tank and then be pleasantly surprised if you really enjoy your meal.
Just the thought of Le Cellier makes me drool. I really think it is fabulous. But I have a thing for beer and cheese soup. Of the two meals I've had there, my whole party thought both were highly enjoyable.
Hope that helps!