Wow! We have such a different opinion. Our family loves the Nemo show. In fact, I think it is my husband's favorite thing is all of Disney World. I like the Lion King show, but I'm the only one in our family that does!
We had not done the bird show for many years (we really enjoy the one at Dollywood and felt the one at AK was not nearly that good). We happened to be passing by in January when a show was starting and decided to try it. We were surprised that we very much enjoyed the new bird show and thought the Up characters really added to the fun. So, it might be worth seeing if you can slip it in, but I wouldn't choose it over Nemo or LK. They are both just much bigger productions.