Some input to reserving the alternate restaurant on board the Infinity:
The service in this restaurant was absolutely wonderful, however we did not find the quality of the food to be worth the extra $25 per person charge.
If you enjoy tableside presentation and preparation of your food( i.e. flambe items)
make sure you ask the maitre d' to reserve you a table next to the preparation area. Because of fire restrictions, they have only one area where they do the flambe, it is not done beside your table.
Generally speaking, we were glad we experienced this one time, however we would not repeat. Bear in mind, however that we did overhear a conversation by someone who was returning to the restaurant for the second time during the cruise.