American Football (especially college) is a better spectator sport - it's the closest thing to watching Roman gladiators this side of the UFC. The plays - offense and defense - are VERY complicated if you choose to follow it at that level, but even a basic understanding is enough to enjoy watching.
Soccer is a much, much better sport to play, especially recreationally. Can play it until you are much older, less likely to get injured, better cardiovascular health, etc. Soccer has a better flow, as the question seems to imply, but in my opinion only set plays such as corner kicks match American Football's excitement for most spectators.
I coach and have kids in "select" soccer (U-9 and U-10) and hope they NEVER play American Football. Too many 40 year olds limping still from playing even at the high school level. But nothing like watching the Ohio State Buckeyes on a Saturday! Go Bucks!