Travelling to Ushuaia is very long and tedious, especially if you are on the early flight from Gatwick to Madrid (8 hour wait at Madrid), and even if you have been checked straight through to Ushuaia, you need to collect your baggage, even if you have the domestic flight from the international terminal (very confusing....nearly left my luggage at BA airport).
3 days travelling on board without setting foot on land, can seem a long time, but there are presentations given by various members of the expedition staff that give you an insight to the Antarctic region, its wildlife, and history. You can also go on deck if weather permits, or up to the bridge viewing platforms to pass the time of day and take pictures of the birdlife, or icebergs on your journey south.
Once you make your first zodiac trip though, everything previously is forgotten, and take Paul’s advice....don’t have your viewfinder surgically implanted to your eye, make sure you take stock of where you are, and enjoy every moment of it.
We were lucky with the weather, and only missed 1 landing, but be prepared that if the weather is bad, you will not be able to go ashore or do the zodiac cruises, and be prepared for some ‘iffy’ moments on the zodiacs if the sea is a bit rough. It was my first time on zodiacs, and now feels that I could cope with anything.
It didn’t happen to me, but remember the Aerolineas Argentinas weight restrictions for hand-luggage; 5kg. If you can put your camera equipment in a backpack and have it on your back, they don’t seem to mind. Also, leave room in your case/bag for the Quark Parka. I wore the inner fleece for flying and packed the outer shell, but still fairly cumbersome.