If you're a real football junkie, Madden's version is probably worth the extra scratch; in addition to that aforementioned polish, it's got a full management game, and Gameloft's game has you sticking with whatever team they give you. Additionally, Madden's got a playoff mode and a nice community behind it, and obviously, since Gameloft's dropping the price, they're basically declaring a surrender to the bigger EA title.
That's fine, though. The cheapskates among us who don't mind a pared-down pigskin experience still win. You can grab NFL 2011 for just a buck "for a limited time."