Would be grateful for any feedback on Alaska cruises on Radiance or Serenade. Also we have only ever booked basic outside stateroom with balcony and are thinking of upgrading to junior suite or grand suite. The main difference I can see between the two(besides price, of course) is sq.ft. and concierge service. Is concierge service that much of a plus? And how long can I safely wait to book these categories, hoping for a price break, before they sell out? I notice that usually if you check within about 3 or 4 months these categories are unavailable.