We did Coral Reef last November. The best way to describe the setup of the place is that it's kind of like a dinner theater setup with not-so-steep stadium seating. We sat in kind of the middle row, furthest right (when facing the tank). We had no problems seeing fish, or the tank, from where we were. That said, if you're seated in the way back, you can see the tank, but I'm not so much sure about how many fish you can see. I personally liked where we sat, since we were close enough to see, but not so close that we had a lot of foot traffic. Up front, a lot of people squeeze in to get a peek of the fish, which lead to a tantrum and food spillage of one of the folks out front.
As far as food goes (we were on
DDP), we thought it was the best we had on our whole trip. I had a shrimp pasta in cream sauce, my husband had Mahi Mahi, my sister king crab, and I don't remember what my BIL had... But we all thought our meals were spectacular. Our waiter was awesome, super friendly, super fun, an absolute riot. I do remember my husband was not-so-impressed with the lobster something-or-other soup he got as a starter, but seeing as we're from New England, we're pretty hard to please on the lobster front.
Now, we had advanced reservations for (I think, 8:30) so we were seated for our meals in about 10 minutes, but when we ate there it was Epcot's EMH, and the waiting area was packed. I don't think that, if you're walk-in foot traffic, you're going to have a better shot at getting seats because of EMH.