RedOctane was bought out shortly after the release of their first game, Guitar Hero - something to be grateful of since Harmonix, the ones who created Frequency and Amplitude among many others were the ones who did it. With this in mind, you can expect the game to be even better.
The new Cherry Gibson SG guitar controller is much, much better and easier to use than the original; unlike the first all-plastic controller, this one has resin on it that makes hitting the notes easier. Also, the note buttons, whammy bar, and strummer work better than before. And who can pass up the Cherry color?
Like the controller, the gameplay is much improved on as well. Hammer-ons and pull-offs are easier this time around; where you had to have nearly perfect timing before, this one gives you much more lenience when hitting them - avid guitarists might frown upon this, because you can just touch the notes to play them. Easy mode is still easy, but expert mode has you playing every single note. The user interface is improved, showing you a statistics screen including how many notes you hit, your average multiplier, and the percentage of notes you hit correctly in each section. And FINALLY, you have a Practice mode! There are more songs, and a wider variety of them too, including death metal and techno.
It still has flaws. One of the more noticeable flaws occurs when you start a game on another difficulty. When you switch difficulties, your guitar stays the same. This means that when you unlock the Grim Ripper in Hard and go to your game on Easy, your character will have the Scythe guitar. Or when you pick the Cherry Gibson for Expert, your Grim Ripper on Hard will be using the Cherry Gibson, even though he's not allowed to change guitars. Yes, this is a minor flaw, to say the least, but I have to bring it down a few pegs.
Despite this, it's still a great game. Go buy it. Go play Free Bird.