How about 1/3 the cost? You can't quite compare apples to apples, as the dates and ports are a bit different. Also, the MSC concierge seems to have, IMHO, a bit more to offer. But, if you compare peak time 2018, 7 night med cruise (because comparing for 2017 would inflate the price of
DCL I think) it breaks out like this for 1 adults, 2 kids per room which is how we travel with our 4 kids. The first two MSC prices are for this summer and is their "fantastica" experience which includes dining, free room service, beverage coupons, cooking and language classes for the kids along with the kids clubs, all shows, plus other stuff. The prices aren't exact since each sailing is a bit different in price. Most of their summer 2018 itinerary is not out yet, as far as I can tell, so I can't directly compare 2018 DCL to MSC.
Balcony DCL $7500, MSC $3000
Oceanview DCL $6000, MSC $2000
Concierge (not a suite) DCL $14,000, MSC Yacht Club $4,800
Yes, the DCL rooms are a bit larger, Yes, MSC has a casino. For that price difference, I can handle it. And since we really cruise for the ports, I am hoping we'll be happy to appreciate the difference to the two lines and enjoy our vacation.
For MSC, if you want to do interior rooms, or a slightly more basic package that is just dining, it's even cheaper, but I can't compare prices because they're basically all sold out.