My partner and I, along with our 14 yo daughter (New Zealanders) recently spent a month (Dec 2018) in Europe including two cruises, one on the Costa Luminosa (out of Venice) and the other on the MSC Meraviglia (out of Rome). The following are my thoughts on comparing the two:
Foremost I would like to say that we had a fantastic time on both cruises and staging a cruise for 2-5 thousand people is obviously a mammoth undertaking requiring staggering resources and organization. People come to cruises with very high expectations and it is always possible to set your expectations in the realm of fantasy, such that they will never be met.
On the Luminosa we booked a suite, which included a comprehensive drinks package, and on the Meraviglia we booked a balcony cabin and bought the comprehensive (but not premium brands) drinks package. The total cost of both cruises (excluding excursions) came to within a few hundred dollars of each other (US$2,830+/-).