I've done that crossing quite a few times back in the days when I use to live in the UK on ferries, something similar to a catamaran and even hovercrafts.
Then I started using the Eurotunnel and stuck with it.

@paolo The Eurotunnel is fine, but for me, it's the feeling of going to an island that is important.
On the other hand, the few times I went by Eurotunnel, the train was always late, even worse, I had an accident IN THE TRAIN when the car in front of me was in reverse gear when trying to get out of the wagon.

But I am sure a lot of people who need to make the passage on a more regular timescale are right to use the tunnel.