Radisson cruises to Alaska are always Country Club Casual. So are their cruises to French Polynesia. We just returned from the Paul Gauguin in French Polynesia. Although I took a sports coat (no tie) for the Captain's Welcome Party, I don't think I was in the majority.
For the rest of Radisson cruises, you will have a mix of formal, informal, and CCC. On Seven Seas Voyager and Mariner, there is always a casual dining room. However, they do ask you to follow dress code in rest of ship. Informal require a sports coat for men; tie is optional.
Radisson is definitely more laid back than the other luxury lines; however, they still maintain a sense of decorum.
I would select Celebrity for a reasonably priced cruise with an upscale feel. They just do some extra's that other cruiselines don't do. Like: Greet you with a drink when you come aboard, ice cold towels waiting for you when you come in off your shore excursion, folks waiting on you and helping you even in the buffet lines, room service that is quick and you can have a full menu, therapy pools that revitalize you and on and on!
BASE cabins on Seven Seas Mariner and Seven Seas Voyager are about the size of Sky Suite on Celebrity. Along with free wine and booze at dinner, you get a bar set up of two litres of liquor. All sodas and bottled water included. All tips included. No set seating. You can dine whenever and with whom you want. Paul Gauguin is only 320 pax, Seven Seas Navigator 490 pax, while Voyager and Mariner are both 700 pax. Passenger to crew and space to passenger ratios among highest at sea.
All this for about the same eventual price as a Sky Suite on Celebrity.
Marc.. I've sailed Radisson once, and Seabourn twice. And no doubt both offer excellent products.
I know on Radisson you get the two litres of liquor in your cabin, and complimentary wine with dinner. But, when I cruised them other drinks onboard, including dinner were charged to your shipboard account. Has that changed?
Even adding in the $140 tips, and the $40 for the two bottles of liquor, I think you'd have to drink an awful lot of wine to bring the cost of a Radisson cruise in line with the cost of a Celebrity Sky Suite.
There's also a value in the amenities that Celebrity offers with their butler service, which Radisson doesn't offer.
Radisson does occassionally offer 2 for 1 sailings, but those are also likely at times of year when other cruise lines are discounting as well.
I do agree, if the OP wants to experience a "luxury" cruise experience, Radisson Voyager would be an excellent choice, but I can't agree that the costs would be the same.