I have been on the Constellation before & taken several other Celebrity cruises.
We did a late check in at the port in Venice with a group of 14 and there was no assistance with baggage getting into the check-in terminal.
The ship lived up to expectations, as variation seems to only be in floor plans and overall size of each ship. The crew was friendly & helpful. Cabins remain about the same, but certain amenities change by ship.
Cabin was OK. The shower had some mold in it.
Took a private walking tour with Splitwalkingtours.com & it was fantastic