It is a kind of "which of your kids do you love the most" question. The differences are fractional, almost so slight as to be nonexistent, but I think I'd go with:
2011 - This championship gets bolstered by the incredible championship run in the Big East tournament. That was just magical and by the end of it I felt like no one in the country could beat us. Of course Kemba also pumps up this championship. We've had a lot of great players at Connecticut, but I don't think we've ever had a more charismatic or electric player than Kemba Walker. He was a special kid.
2014 - I struggled with this a little bit versus 1999. Watching Bazz and Boatright just utterly dominate opposing guards completely taking other teams out of what they wanted to do was amazing. This team had a certain sense of inevitability about it as well. You knew we were going to make our free throws down the line and I love the fact that Calipari didn't even try and foul us. I will always love Bazz standing up at the end of the game and calling out the NCAA, just classic. 'You banned, this is what you get.' Beating Kentucky doesn't hurt it this championship either.
1999 - You never forget your first. Ricky Moore's unstoppable first half offense and dominating second half defense was incredibly impressive. Of course the fact that we beat a supposedly unbeatable Duke team also helps this championship. Rip Hamilton's relentless energy and KEA's "we're going to shock the world/we shocked the world" help this championships ranking.
2023 - This one benefits from recency bias. It felt so good, though, to be back on top. This program has been written off for dead so many times and so many try to discount or ignore our consistent excellence. This year's championship was just an exclamation point about who we are. Andre Jackson is a special kid who is easy to root for. Sanogo had a great run for us and it was good to see it culminate in the championship. Clingan and Karaban were both surprises. You knew they were going to be good, but to be as effective as they both were in there freshman years was the difference between this being a good team and a great team.
2004 - It feels weird to rank this team last in anything. It had to parade high school all Americans (Anderson and Brown) and six future NBA players (Gordon, Okafor, Villanueva, Armstrong, Williams and Boone). It may well be our most talented team. Watching Calhoun out coach Krzyzewski was just a pleasure. It was a little scary when Okafor had to sit down, but in the end that was likely the difference.