You'll hear lots and lots of different opinions, but I think it is definitely worth doing at least once. DH and I attended last summer and loved it. We had a table for just the two of us and we didn't feel crowded at all. We had a great view of the fireworks and we didn't even have to stand - we could see everything from our table. We didn't have any problem seeing over the heads of the people who chose to stand at the railing.
The desserts were good, not great. There is a TON to choose from - chocolate covered strawberries, cookies, cheesecake....you name it, it's probably there! They offered various hot and cold beverages as well. Make sure you either eat a very, very light dinner or skip dinner all together!
We're hoping to do it again with my parents over Christmas since it will be their first time at WDW, but it probably will be a few trips before we do it again. If we had liked the desserts more, I think we would be more inclined to do it on every trip.
Here's a link to a good review from AllEars:
http://goo.gl/u19En
Enjoy!