Hi mizom58, and welcome to cruise-chat. And, contgratulations to you and your spouse on your 25th anniversary!
The answer to the question is whether you want the ship or destination to be the main attraction. The Explorer of the Seas itinerary has you docked in Bermuda for about a day and a half -- and in a section that has less to offer. The Empress of the Seas itinerary spends more time in Bermuda, and you will also dock in two ports that have more to see and do. Additionally, the two ports on the Empress of the Seas itinerary are going to be phased out in the years ahead, so now's your time to visit.
But, if it's the ship that's the attraction, you can't go wrong with Explorer of the Seas. And, if time is a consideration, it is possible to visit the other two ports from King's Wharf (where Explorer of the Seas docks); it just takes some time.