We went for our first family trip to WDW last May DH (me), DW, DD14, DD12 and DD8. We stayed at the Poly, and did both the Spirit of Aloha and Ohanas, as part of the theme of our trip. I won't touch upon the "worth" aspect of your query, but I will at least give you my impressions, good and bad.
We did Ohanas first, on the day we arrived. We were sat at a table away from the main "action", but that was fine with us. They have games that the kids can get involved with, so I took my DD8 up to enter the coconut race. This took a LONG time to organize, because they seemed to want to get every child into one race, rather than just doing several. Normally, I wouldn't care, but when we got back to our table, some of the food had arrived and was getting cold.
The waitress was ... adequate. For some reason, she seemed out of place. I couldn't help thinking that she belonged in a country-style family restaurant, rather than a "island" themed restaurant. She looked dumbfounded when I asked for coffee at the end of the meal!? I didn't understand that, but it did give DW and I a chuckle. She spent far too much time at a neighbouring table, trying to get the kids there to eat. Isn't that the parent's job?
We enjoyed the food, all very tasty. The steak was cooked more than I like, but I was expecting that because of the way it is served. It was still tasty though. The food came promptly, if anything a bit too fast for us. Of course we ate too much -- this would become a recurring theme as we were on the
DDP. I ordered one of those rum drinks in a pineapple (forgot what it is called) and split it with my wife. We don't normally drink much rum, so it seemed strong but we still enjoyed it.
We did Spirit of Aloha later that week, on a Friday night. There was a very long line-up, and it took a long time to get in. Fortunately, it was a nice evening, so we did not mind waiting. Eventually though, they came and told us that if we did not want our picture taken, which involved extra $$$, we could go in a much faster line.
The seating layout was the biggest disappointment. (even though I had paid extra for tier 1 seating). The tables seat maybe 9 people(or was it 11 or 13?) and you have to look along the length of the table to see the stage. We were seated at the far end of the table. Too make matters worse, since people like to take photos or movies, hands and cameras are constantly out further blocking your view. If you manage to get at or near the very front of the table, I'm sure it would be great.
The show itself is two parts. The first was a rather corny, predictable "love/ugly duckling" story. However, the second part involving various native dances was quite entertaining, particularily the fire dance.
We enjoyed all the food, particularily the Pineapple-coconut Bread. Again, we ate too much. The price includes all-you-can drink beer and wine, but we are small drinkers so that was not much of a bargain for us.
The waiter was fine - professional but not as sociable as I would like.
Overall, we were glad we did the show, but would not do it again.
We are thinking about returning to the Poly in May 2009, when I think we will try something new and eat at Kona instead.