First off I realize this is somewhat apples and oranges but I'm basically talking about entertainment value here. The fact that they are both called football helps.

In no particular order…


Field of play
The grass is greener. For me part of the viewing experience is based on natural turf.
It's simply more pleasurable to look at a natural green turf as compared to artificial turf.
Yes some of the new turfs are better aesthetically but you can't beat the real thing
There are those that say artificial turf brings more certainty to the game, a "level" playing field if you will.
I say balderdash to that. Some of the best football games ever have been played under horrible field conditions on natural turf.


Stadiums
Generally smaller than the NFL most EPL stadiums provide a better viewing experience. Fans are closer to the action. Enough said.
Being outdoors again adds to the experience. You don't smell the person next to you as much as you would indoors


The Clock
This may be the most important factor of all. Most NFL games run approximately 3 hours. Of this time you get under 20 minutes of on field action.
At home this means you're basically watching commercials.
The EPL runs two 45 minute halfs with added penalty time (the clock never stops) and this translates to NO commercials. Unbeatable.


Players
Basically no equipment in soccer so player identification is a big plus for the sport.
This is especially important when you're new to the game.


The League
This topic is not so cut and dried. First of all there are no playoffs. At first glance this seems ridiculous for a North American. The playoffs are everything here. If you can squeak into the playoffs then the unthinkable can sometimes happen.

In the EPL as we see today, the title is basically wrapped up with a few months to play.
The only drama from regular season play is relegation. Relegation drops the bottom three teams out of the league. That's plenty dramatic for those teams.
The argument for the playoff system is valid but it means the regular season is often less meaningful.
Winning team gets 3 points, 1 each for a tie. No overtime. This puts the NHL point system to shame.


Penalties
The penalty system is beautifully simple. Commit an average foul and you get a yellow card.
A second similar foul and you are sent off with a red card and your team plays short handed. An egregious foul can bring about an instant red.
I think you also miss the next couple of games if red carded.
The referee has a more important role. They typically gather the offended and offender and give them a good talking to.


Fans
No chance of matching the passion of the fans. The experience of being there must be great as the fans for both teams spend much of their time singing or chanting.
Even through the television this is impressive.
The opposing team fans travel in large numbers and are designated seats together at one end of the field. Nothing like it here.