Voice control IMHO adds so much to the immersion to the game. I try not to use the UI at all which means going to the appropriate station to look at gauges etc for the information that you require, ordering the crew to perform various tasks and generally conducting yourself like real Kapitänleutnant used to.
The only thing you need the keyboard for is to walk around the boat or rotate the periscope. It's great looking through the scope at a target and saying "Target speed...6 knots, Range...1300 meters, AOB...60° Port" and having the crew input the data into the TDC as you speak and then "Flood tube 1....Los!" and have the torpedo leave the tube and head for the target. It is also fun trying to scramble down the conning tower ladder as fast as you can after spotting an aircraft heading your way, and yelling "Alarm!..Alarm!" and hearing all hell break loose as the crew start to crash dive.
