If you want to see the fastest athletes on earth in a team sport, going 100% and making some bone crushing hits at full speed, you will watch football. There are breaks often but it is needed when you are going 100% nearly every play.
If you want to see some fast athletes but more with better aerobic levels than NFL players, you will watch rugby. It is a slower game with the occassional big hit but it is usually all moderatly paced. There are no timeouts as previously mentioned.
Both bring something completely different to the table but both are fine in their own outright. Personally, I like the faster pace and bigger hits of the NFL. 99% of overseas people will prefer what they are used to and call the NFL a pussy sport because of the pads and timeouts. To each his own.