The GHIII demo was released today (10-23) on Xbox Live and features five songs: "Lay Down", "Hit Me With Your Best Shot", "Even Flow", "Rock You Like A Hurricane", and "The Metal". I'll just review each song, one-by-one. [Note: I play on Expert, so my review's based on that difficulty.]
"Lay Down"/"Hit Me With Your Best Shot": 3.5/5 I'll just review these two songs together. While they're both somewhat catchy, they aren't too fun to play on Guitar Hero. They're quite repetitive, and very easy.
"Even Flow": 4.5/5 While it has a somewhat repetitive main riff, Pearl Jam is a great band, and this is one of their best songs in my opinion. While not strenuously difficult, in anyway, it's fun to play.
"Rock You Like A Hurricane": 4.75/5 Difficult, and a lot of fun to play. For the most part, the song is very easy, but the whole guitar solo in the song are far from easy. Getting the first star power sequence your first time trying the song won't be likely. One of the best, if not the best, songs in the demo.
"The Metal": 4.75/5 A pretty short and fun song. The main riff is a lot of fun to play, and the song has some hard to get chords, but you'll get it eventually. Not the hardest song ever to be in Guitar Hero, but it's definitely fun.
The Guitar Hero 3 DEMO isn't really fantastic, but isn't bad at all. There are three very fun songs, but two songs that are really boring and easy to play. Hopefully, Neversoft has less of the bad, and more of the good in the final game. We'll just have to see on the 28th.