Yeah takes about 20 minutes and it is really cool at night. Kind of mysterious back in the dark channel and then as you get towards DD it's all lit up and festive!
Agree with the 15-20 minutes for the actual boat ride from the time you leave POR to arrival at DTD. Depending on the boat schedule, you may wait 5-10 minutes to leave. It was definitely a fun way to get there, especially when you are sick of taking the buses everywhere.