My husband and I dined there on Valentine's Day this past February, during Wishes! I know that there are better (and less expensive) places from which to view the fireworks, but our window-side table was pretty incredible. In fact, when we were sat at our table, I cried a little. No kidding.
As for the food, I would say it is ABSOLUTELY, 100% worth it. We ate at a number of signatures during our trip and California Grill was by far our favorite meal. It is the only meal that I can rank up there with the best meals I've had in my life, and I've eaten at some wonderful places.
I could definitely see the menu not appealing to everyone (although so many things appeal to me!), so check the menu out and make sure there items on it you would be interested in. Be aware that the menu changes frequently and not all items are always available (although many seem to always be there).