We just got back from our first Disney trip 2 weeks ago, and ate at both of those places for the first time.
The food at Le Cellier was excellent - if you're into steaks and things. My kids got a little bored midway through the meal (they're 7 and 4), but it was worth it and we'd definately go back.
The food at Coral Reef was subpar - I wouldn't even compare it to Red Lobster. I was definately not impressed. The kids were silent the whole meal, though - which is a plus - mesmerized by the aquariums (we waited and got a glass/water-side seat). I doubt we'd go back just because of that one factor. If we want good seafood, we'll visit Fultons or elsewhere.