I'm on the Millennium in April (the 8th)! I took her sister ship, Summit, out of Puerto Rico in 2018. I love the port calls from there. Neither had gone through a revolution at the time.
Well I might be able to try the food out for you! My hotel before my cruise in April is right by there. I did want to try Barrachina's for dinner though. I'll make a reservation for that!
Just had a mini panic! I booked an 8th deck aft a few days ago on Horizon (specifically for their Havana) and had to double check my booking. That's odd that Vista only goes up to the 7th for the aft extended. I wonder if they have more Havana rooms elsewhere that Horizon doesn't have or if Horizon just has more Havana rooms.