We were on MSC Fantasia in Oct 2019 for a 7-nights western Mediterranean cruise. This was our 5th cruise overall and 2nd on MSC.
MSC Fantasia, by today's standards, is not a big ship. But make no mistake, it's still about 130,000 tons. I believe she's about 10 years-old now, but incredibly maintained. You have to be deliberately looking for rust to spot rust. The only 2 rust spots I saw: lower balcony railing on the OUTSIDE of balcony glass. As I said, you have to be actively looking for them. Crews were always doing preventative maintenance when passengers weren't around (late nights & port days). They even re-tiled a hot tub in 2 days during our cruise. I have new found respect for MSC after this cruise, especially after two cruises on older ships on NCL and RCCL.
The only way you can tell it's an older ship is the design and decor of public spaces. Fantasia's decor seemed to be stuck in between the late 90's and early 00's, with a mesh up of traditional colors (gold, chocolate/brown, mahogany) and modern (glasses, mirrors & chrome). I'm glad MSC ditched the color scheme on its newer ships. As it stands, it could be off putting to some. Public spaces are pretty scarce if you are not booked in Yacht Club. Pool decks are disjointed and requires traversing different decks to go from bow to stern. Atrium is small for a 130,000-tons ship. Regal Princess has about the same displacement and a much larger atrium.