We stayed (the wife and I) last Feb. at the JW, but ate more meals at the Casa Magna than the JW. They are both really nice, but if you are taking kids, as we are again this Feb., I'd stay at the Casa Magna. The JW seemed a little stuck-up, the Casa Magna more relaxed.
My suggestion is to eat at the hotels as infrequently as you can. You can get the breakfast if you are not using points. Go to tripadvisor.com and look up both hotels. You will see many suggestions as to where to go for meals--some just a short walk away from the hotels.
Either way, you'll love it...we did and that's why this time we are taking the boys with us.