I’ve been on two cruises with MSC, including the Preziosa but have never cruised with anyone else so I have nothing to compare it to.
They are very casual (according to my friend who knows these things) I can only recall one theme night- white night- but it isn’t enforced. The 24 hour buffet is good and you can also have served breakfast and lunch in the main restaurants to avoid the horror of other people. We didn’t get a drinks package, mostly as a motivation to not drink so much alcohol so we ensured we stayed under the price of the package. To be honest I’m not sure I’d ever get a drinks package. We also didn’t bother with the internet package to ensure some downtime.
Lots of nice bars with music and entertainment every night. Not an awful lot of programmed things in the daytime and the pools were too busy for my liking. However one good thing that I would recommend is booking a treatment- massage or so- and your package should include entry to the saunas, jacuzzi etc all day long
Out first cruise was in Norway, we did an excursion with them into one of the fjords and an excursion with another company at one of the destinations. Nothing else really tickled our fancy and the boat was so close to the city centre in all the other towns that we visited that we just amused ourselves with help from The Rough Guide.
The second was around the Baltic Sea (Tallinn, Helsinki and Stockholm- that was the Preziosa) again we just figured out the local public transport and amused ourselves.
If you have any specific questions let me know and I’ll try my best to answer!