We sailed on the Explorer from Seward to Vancouver September 13. Received an email from Regent a few days before we left for Alaska offering upgrades, and we upgraded from Concierge to an Explorer Suite (some say former Seven Seas Suite), Suite 1011, for what I viewed as a fair cost. Great Suite. Seems to be below the smoking area on the pool deck. Since it was an Alaska cruise and the weather was cold, no one was using the pool deck but on one or two occasions we did hear furniture being moved in the morning.
I would book this suite again, even if not getting a discounted upgrade price. Everything about the suite was great. The actual door between the bedroom and living area allowed my wife to sleep in while I get up a bit early. It has one and one-half baths. She did not even hear the coffee maker which was a bit loud. We would have liked to use the balcony but the weather was not warm enough. On our second to last night they tied down all the furniture as the seas were expected to be rough. There was one night that it was pretty rough all night. The night they tied things down they said it would be rough for a window of time (about three hours) and they were spot on. If money was no object, I would probably book the Grand suite next door or across the ship (1012 or 1015, respectively).
Only peeve about the ship, and it is a first world peeve, is the advertising for "distinguished suites" online and also in their printed literature suggest that the Distinctive Suites are entitled to guaranteed specialty restaurant reservations. (https://www.rssc.com/experience/suites/distinctive-suites). That is only true for Regent, Grand and Master suites.
My only other peeve is the included lodging in Anchorage was the Hilton, and it was pretty run-down.
We are looking at a 19 night mediterranean cruise on Regent for 2025.