The things football and rugby have in common is that they need the same limited tackles and scoring touchdowns.

The differences between them also is that the balls being used are very different from each other. Also for rugby you don’t need to wear all the equipment, but for football you need all that gear to be safe. 

Also the game length for American football is 4 quarters and it’s 15 minutes each. For rugby its 2 halves and each is 40 minutes. Also the weight of the ball is very different from rugby and football. But in my opinion I prefer to play rugby. If I had to choose I wouldn’t really play this, it’s just if I had to do this as a sport.