The reviewer "Regent Ain't What She Used To Be" provides a detailed review we entirely agree with. Unlike that reviewer we had not sailed with Regent before. Our cruise experience was with Seabourn. We believed the two cruise lines were similar. In our experience they are not.
Seabourn prides itself on the interaction between staff and clients - this is the major failing we found with Regent. As noted by other reviewers, staff seem overworked and undertrained. Many categories, such as the sommeliers throughout the ship, are sommeliers in name only. They could offer, poorly, the wine of the day, but struggled to deal with any request beyond that.
More generally we made a number of inquiries with staff, none of which were adequately dealt with. The answer typically was "I don't know", there was no offer of follow up or further assistance.