If you can’t choose between Channel Tunnel and ferry, certainly choose ferry. WHY?
1. It’s more comfortable to lay on sofas (you have to go out from bus/car) than sit 2 hours in an absolute darkness. But the best thing you can do on ferry is to enjoy the view. You can sit down in hall and watch how the famous Dover’s white cliffs are approaching.
2. You can also shop there in a lot of stores. One is a huge drugstore – something like Sephora or Douglas, where you can buy literally everything – from The Body Shop products to expensive Dior cosmetics. Then you have there a shop with souvenirs and Cadbury chocolate or Strarbucks.
3. You can also go out and watch the ocean from the external deck – or just a space behind the windows you watch through from inside.
Bad thing about ferry is that it very swing, so people with a weak stomach will probably vomit
Sometimes isn’t on ferry any free space so you have to wait for the next one.
Ferry goes from Calais in France to Dover in England. In Calais is a passport control. The controlers control passengers’s bags sometimes, so you will maybe stay in Calais more than you thought.