If I flew enough on United, E+ would be the most important reason for me to stay with them.
Yet, at the same time, as a leisure traveler that travels once or twice a year, i'll go for either price or IFE....
Basically i'm saying, as a frequent flyer, E+ is more important, but as a leisure traveler, i'm not spending the extra money buying myself up to E+ and dont get to experience it... hence i prefer IFE (though i'll fly any airline if the price is right).