This is a hard choice.
Probably a bit more lively.
Probably better overall food.
Jewel of the Seas:
BEAUTIFUL ship and decor.
smaller standard cabins (but more than enough for two)
Food is fine.
I have to say that the Jewel class of ships are some of my favorites. They have a great layout and beautiful decor with a lot windows and open space. You always know you're at sea.
For me: Even though I enjoy Carnival's food more, I would go with Jewel OTS. I just love those ships. If you can swing a mini-suite or suite you will REALLY love it.