Any opinions on Citivecchia
Joe, Civitavecchia is the port the ships use for Rome. It's about an hour or 90 minutes into Rome from there. If you sign up for a tour through Costa, the price will include transportation to and from Rome.
I've sailed twice on Costa, but not on the two ships you're considering. I enjoyed both cruises. We were among only about 5% English speakers onboard both cruises. It was great fun sailing with mostly Europeans, although they do like to smoke a lot!