there is no comparison.
rugby is a game played by men with odd shaped balls.
nfl is a game played by men with odd shaped arses.
A tale from reidy's travelog
went to vegas, and in the taxi from the airport the driver immediately picked my accent to about 4 miles accuracy. turns out he spent his childhood living at Burtonwood as his arl fella was in the u.s. airforce, he was really into rugby league and had followed 'the wire' since his boyhood days. he said that they used to play gridiron and had their own league set up at the base.
anyways, for some reason he ended up meeting some local kids and going to watch a school rugby game (league), he got the kids invited to the base and stuff to see some bombers and shiz, and they had a rugby ball, so they had a throw around locals v imperialist aggressors, now he said that kids used to play gridiron in shorts and t-shirts when messing around but they got absolutely mashed by these warrington kids and most refused to play unless they could put their uniforms on (helmets).
rugby league and more these days union since the arrival of professionalism and pacific islanders, kiwi's and aussies is a far greater tempo than NFL, there is no time for recovery, you get hit and you have to get back up and get straight back on with it, you have to get back up and play the ball for starters. for me it says it all about NFL when someone says that remotes have a pre-set function to advance past all the crap that goes on between plays etc. and that the ads are as big as the event.