We have been cruising with Celebrity for the last 5 years. I personally don't want to change cruise companies since everything we want on a cruise, they offer.
The staff on the Infinity are amazing. They are friendly and cannot do enough for you.
The ship is very comfortable and just big enough that it doesn't feel at all crowded.
The food is great and plenty of choices. One thing that I ate a lot of were green apples since they help when you feel a bit queasy.
We actually met a person that was our waiter about 1 1/2 years ago. He didn't remember our names but he did remember that my husband took fruity loops for breakfast. I must say I was really impressed.
I would do this same cruise again in a moment. 17 nights give you plenty of sea days which I think are the nicest. Don't mind going ashore now and again but we prefer the sea days.
The lectures are very informative and we try to attend them. If you are planning on going through the Panama Canal I would advise you to attend them since they give you a lot of good information.
There is so much to do on the ship if you want to be busy, but we tend to do our own thing.
This is the 2nd time we went through the Panama, it's interesting all the things that you miss the first time.