I think which would be best may depend upon the person using it.
I tried bonine on our last cruise...it didn't work well enough for me, I had to go to the Purser's desk and get some dramamine.
When hubby and I were on our first cruise I didn't even think about sea sickness, even though I know I'm prone to it, so I wasn't prepared at all. Got REALLY sick the first night out. Next morning one of the crew saw me looking so GREEN and suggested we callt he ship's doctor and get a shot for it. I don't know what it was, but I got the shot and within 20 minutes I had my sea legs and didn't need anything for the rest of the trip. Plus you could drink (although I don't drink much).
I'm probably going to take dramamine this next time, with theknowledge that if it doesn't work, there's always the ship's doctor to give me a shot!