We've been on several Carnival cruises and much bigger ships, but the Paradise (and by extension, the Fantasy-class) still is a lot of fun. It recently got upgraded with Guy's Burger Joint, the Red Frog Rum Bar, and the Blue Iguana Cantina, and some waterslides were added. That being said, you can tell it is an older boat by the interior design -- you have to up or down to get around the Elation (mid-ship) dining room and some the paths you have to take are not intuitive like some newer ships. Regardless, we had a lot of fun!
We had an aft interior cabin. It was small, we knew that, but it wasn't nearly as small as an interior on the Royal Caribbean Majesty of the Seas. Very comfortable, and all 4 of us could see the flat-screen TV in the room. Our room steward was very nice and kept the room spotless.
Dining was ok. Guy's has the best burgers at sea as far as I can tell. The tacos at Blue Iguana were delicious and the line moved quickly. Paradise has the new Sea Day Brunch menu and, for me, the jury is still out. I think I liked the old menu more. Dinner was a little bit of a let-down. Everything tasted good and as it should, but there was no "wow." No escargots. No Beef Wellington. No surf-n-turf (without a $20 upcharge). No Baked Alaska. No Grand Marnier Souffle. And Paradise has no steakhouse.
Service is generally were Carnival excels, and Paradise did not disappoint. From the cabin steward to the waitstaff, service was onpoint. Our only disappointment was a solitary bartender at the Rotterdam bar outside the Queen Mary Lounge -- he had a sour attitude the entire week, and I don't know why.
Small, but efficient. 1 lower king, 2 upper twins. Flat-screen TV, 3 closets. Efficient bathroom. I do wish Carnival would do like NCL and install glass shower enclosures because the shower curtain does conspire to wrap itself around you!