Direct flights were expensive so we flew via Madrid. We booked with BA through tripadvisor/lastminute.com. However, the long flights were code share with Iberia. Iberia charged us £25 pp per flight but it meant we had 2 seats together in a block of two next to the window on both long flights - well worth avoiding the risk of not getting good seats.
We booked a one night pre-cruise stay at the hotel Esplendor on San Martin in Buenos Aires with last minute.com (£57 c.f. £200 with the travel agent). They were undergoing road repairs outside – did not affect us in any way. It is a good value 4* hotel near to the port ($3 taxi ride), Florida Street and other attractions such as the national monument. Breakfast was at least adequate. When we booked the cruise, a few weeks before, the official rate was 6 pesos to a dollar. By the time we arrived it was 8. Touts on Florida Street offered 11 but to avoid risk we changed in a shop and got 10.
Taxi from the airport to our hotel with Ezeiza taxis worked a treat as others have described. Go through arrivals and you cannot miss their stand. Paid US$38 and 2 minutes later a taxi driver escorted us to his car. 40 minutes later we were in the hotel. No need to tip although we gave a few dollars which were gratefully received.
No problems. Worth the £300 extra for a window. A balcony is nice and it would be good to step outside for clearer photos - but not worth the £1000 each extra. You will not be sunbathing in Artarctica. If you saw anything to photograph, you could be outside on deck 4 in a few seconds.The cabin steward and his assistant were excellent. Comfortable beds. Clean room. Temperature regulation worked a treat - you start in the heat of Buenos Aires (air conditioning fine) and move to Antactica (heating fine). Lifts convenient. Very little corridor noise.