I've been in 7427 on the Victory and 7448 on the Conquest. Both are 'Aft-View Extended Balcony'. The rooms are the usual tiny cabin but the balcony is about twice the size and the view is wonderful! Please note the divider between the balconies is slanted and you have no privacy. You will get to know your neighbors on both sides. I wouldn't hesitate to travel in either room again.
However, three will be crowded. It depends on how much time you spend in the cabin. I've been in a suite on the Ecstacy and loved it. The suite perks aren't up to the standards of Princess or Celebrity but I enjoyed the extra space.
The wife and I tend to spend a lot of time in the room relaxing. Our last three cruises have been in Princess mini-suites (323 sq ft) or Vista suites (500+ sq ft). I used to ALWAYS regret not spending the money for a suite. Now I just write the check. We are booked in a Penthouse Suite on the Celebrity Constellation for 2014. Still looking at the Triumph for 2013.