I finally got around to picking up Rocksmith 2014, and I am very pleasantly surprised. I had played the original Rocksmith and thought it had a lot of potential, but felt the note detection was wonky, the UI was clunky, and the song list was beyond pathetic. 2014 addresses all of these problems and adds some great new features to boot.
The UI has been improved across the board. The choppy, linear menu system from the first game is gone, with song navigation now letting you sort by a variety of options, similar to Rock Band 2 & 3. The in-game fretboard has been enhanced to show fret numbers, fingering, and chord names, so you have all the info you need to sight read the note charts.
The boring career mode from the first game is gone, replaced by a mission system that leads you through different aspects of the game, including guitar lessons, session play (a reactive jam session where you can tweak just about everything), a vastly improved guitarcade, and different modes for playing the songs in your library.
The song list is now centered around recognizable hard rock and metal songs, with some grunge, classic rock, and modern fare mixed in. This is exactly what a guitar game's song list should be like. I don't know what they were smoking when they came up with the original game's pile of coffeehouse dreck, but they've fully redeemed themselves here. The DLC offers some great options too, like packs of Iron Maiden, Rush, Boston, Aerosmith, Judas Priest, and Megadeth. All of the original Rocksmith DLC works in this game too, and if you're a masochist you can even pay $10 to import the songs from the original game -- but why would you?
My fingers are sore and calloused from all the time I've spent with the game so far. Well worth the price of admission.