There have already been several quite comprehensive reviews of Constellation and the 'Immersive Wine Cruise' she's sailing. Without repeating too much, here are our impressions.
First up, the Millennium Class Celebrity ships are not as new as the Solstice vessels, but its not all bad. For one thing, they carry fewer passengers and so are less crowded. They have also been 'solsticised' which effectively means redecoration and re-branding of some inside venues. Constellation is 10 years old but there is still life left in this ship and compared with the prices you'll pay for a cruise on a Solstice ship, its worth a look.
This cruise attracted a fair few North Americans. Mostly middle aged or retired couples with a passion for Europe and Wine. I'd say they made up around 50-60% of passengers. But if there was any loud vulgarity it wasn't our North American cousins, but the lower end of the cruising market Brits who lowered the tone. We were grateful not to see any football strips being worn though.