I assume you are starting from Bombay/Mumbai and want to compare flying/ferry/train service.

Go and fly. It saves time and you miss nothing much.

Ferry: takes ages and seating is not so good for 6+ hours. Avoid it.

Train: Konkan rail is very nice and scenic, but the stations in Goa are off the tracks and you have to transfer to get to Goa. Rail travel in India is also a nice experience where you get to meet in close contact with the locals. So if you have the time, you could try it.