I am a Carnival Diamond. My wife and I love the Vista for its features and port of Galveston.
This cruise was our worst on the Vista. Much of this was due to the lax cruise director and enforcement (lack of) of policies. For example, debarkation for Diamond (early) is a distinct perk. However, for example, on this cruise they instructed us to be in the restaurant at 8am to "prepare" for early debarkation. However, they actually began debarkation before 7:30am. It turned into a circus. Our visits to our ports was similar. Very poor announcements (cruise director) and enforcement by staff. Several "scuffles" onboard, with very rude newer cruisers not being held accountable. Someone actually "crapped" in one of the stairways. Wow! I would not expect this on a modern cruise ship. Additionally, very few people went to the dining room. The Lido buffet lines for dinner were ridiculous. Should have more open lines.
Cabin was fine, with a few issues (bathroom, safe didn't work, lights flickering). All were corrected by second day.