I have just completed a cruise on Britannia to Spain and Portugal. The cruise overall was fantastic and as such I have booked another on Britannia in June. A more detailed breakdown of the pros/cons are below;
Itinerary - I enjoyed every port we visited, especially Lisbon. The ship docked in each city and no shuttle bus needed.
Ship - The ship is large and was fully booked. However, it was still easy to find sunbeds, book restaurants and find quiet spots to relax. Lots of outside space with magnificent views. There is no central staircase which is a bit stange and causes more lift queues. WIFI was very fast, even the basic package at sea.
Cabin - We had an inside cabin on C deck. This was in excellent condition and really well prepared by the cabin steward. We have never stayed in an inside cabin before, but it was spacious with great storage.