We sailed the Carnival Sensation about a month ago and had a great cruise. Very crowded but never a problem. We stayed in one of the Grand Suites and found the cabin very spacious and plenty of room for 4 of us.
The casino was lots of fun, weather wasn't very cooperative so not much pool time, however, plenty of the usual activities to keep us satisfied.
I love sailing the older ships, they just seem so much easier to navigate and they have upgraded it to include all the fun zones!
Book her, and enjoy!