I can highly recommend Royal Caribbean but maybe consider some of the 12 night Navigator of the Seas cruises from Barcelona to avoid The Bay of Biscay and days at sea. The Navigator is truly a fantastic ship and apart from the flowrider and kids pools has everything the independance has but maybe better prices. One tip is book cruise only and take easyjet flights to Barclona and a taxi to an from the airport you may save around £100 or more. At the end of the day it all depends on the itinery you prefer as there are loads of good early and late booking deals for Oct.
Just a minute....No one can guarantee you storm free weather in October even the caribbean which is the calmest area at that time of year can kick up a storm So
calmest possibility is the Caribbean, Biscay and the Med do have storms in October. ...Nei.