Depends what's most important to you. If I were to choose based on ship preference and proximity of port to home (your home not mine lol), I would vote for the Conquest. Triumph is not really my favorite ship but it's OK.
Now based on port choice and Itinerary I would vote for New Orleans.
We cruise out of New Orleans a lot and it is just easy, not terribly expensive and about an 11 hour drive from our home. We love the food and music in New Orleans and keep going back again and again.
Now if you want the best of both worlds so you can enjoy a larger newer Conquest and sail out of New Orleans to the good scuba ports of Belize, Roatan and Cozumel if you can wait until Nov. 13th for a 7 day, or Dec. 24th for an 8 day that has those three ports and Progreso as well.
If you need the name of some good dive shops in Belize and Roatan holler, will be more than glad to share the ones I have dove with.