We did this as part of a B2B. Summit was a great vacation. Ship facilities and Service was great. Food in the MDR was good but not great. Food in the specialty DR, Q'sine was great but a bit pricey at $45 pp.
We did the Concierge level . Difference between this and standard balcony is you get a table big enough to dine on vs a small snack table on the balcony and you have a love seat for 2 (that opens to a bed if needed) vs a chair for one in the cabin. You get the daily "savories" which is a few bites of snack - nothing much. You also get a bottle of sparkling wine which was a decent quality.
They say this is a limited view room, but what they mean is the design of the ship has some balconies extended a bit further out so when you look (in our case cabin 8047) to the right you do not have a full 180 degree view. Lets just say it's about a 135 degree field of view. Look at some pics of the outside of the ship. We did not find this limiting at all.
Entertainment - Production shows were a little better than we've seen on other ships, and the independent comic and magician were really really good. Alexander the Cruise Director is better than most.
Mineral water pool in the Solarium was wonderfully relaxing.
We've sailed Celebrity, RCCL, Princess, Holland and Carnival. Celeb remains our favorite.